Early warning systems (EWSs) have been defined by UN/ISDR (2009) as “a set of capacities needed to generate and disseminate timely and meaningful warning information to enable individuals, communities and organization, threatened by a hazard to prepare and to act appropriately and in sufficient time to reduce losses”. They must comprise four elements: risk knowledge, monitoring and warning services, dissemination and communication, and response capability (UN/ISDR, 2006). A worldwide overview of existing EWSs for rapid mass movements and for weather-induced landslides is available in Stähli et al. (2015) and Calvello (2017). Based on the size of the area covered by the system, landslide EWSs can be separated into (a) local, focusing on a single landslide at slope scale, and (b) territorial, focusing on multiple landslides at regional scale, over a basin, municipality, region or nation (Bazin, 2012; Calvello, 2017). Stähli et al. (2015) recognized three main categories of EWSs for rapid mass movements: alarm, warning, and forecasting systems (Table 1).

The number of existing territorial and landslide forecasting systems seems to have increased in recent years (Piciullo et al., 2018). Calvello (2017) suggests that this can be due to better cost effectiveness, compared to the realization of structural mitigation measures; easy applicability over large and densely populated areas where the risk to people is widespread; upgraded technologies; and more reliable models in weather forecasts. However, this could also be explained by the fact that several territorial EWSs working operationally have started to become visible in international literature just recently, mainly in the last 5 years, like the EWS from Alerta-Rio, from Brazil (D'Orsi, 2012) operating since 1997. Others are still not well known outside their own region, typically due to a lack of international publication and documentation. This is the case for the Norwegian service, described in this document. It is challenging for territorial and local operational EWSs to reconcile typical operational tasks with research activities and dissemination of experiences to an international audience. Often, especially for territorial services, operational activities and continuous improvement of the service seem to have higher priority than publicizing the latest development internationally. For some services, frequent catastrophic events may also limit the required time and attention to publish articles. Furthermore, documentation is often published in the original language of the service first, sufficient for the direct users, but less accessible to international readers.

The existing operative services around the world focus on prediction, warning and sending alarm to the population about possible occurrence of fast-moving landslides, usually shallow, which are triggered by intense rainfall and/or snowmelt. These landslides fall in the category of flow-type landslides (Hungr et al., 2001) like debris flows, debris flood, debris avalanches, but translational or rotational debris and soil slides can also be observed (Hungr et al., 2014). They occur in steep slopes, usually covered by Quaternary loose deposits (like tills deposits, volcanic sediments, loess, lateritic soils). Because of their long runout and high velocity, they are responsible of large damages and casualties worldwide (Dowling and Santi, 2014). In regions covered by snow, slushflows, another rapid mass movement, may also be triggered during rainfall and snowmelt episodes. Slushflows are movements of water-saturated snow which initiate in gentle slopes and are characterized by long runouts (Washburn and Goldthwait, 1958; Hestnes, 1985). Their high density and velocity have caused dozens of fatalities as well as the destruction of buildings and closure of roads and railways (Hestnes, 1998).

With the general name “rainfall- and snowmelt-induced landslides”, used herein, we refer to debris flows, debris flood, debris avalanches, translational or rotational debris and soil slides and slushflows, because they often occur under the same rainfall and/or snowmelt episodes. They regularly occur in clusters, in large number and scattered over a large area, happening frequently together with floods.

These types of landslides cause yearly significant damages in Norway to roads and railways, buildings, and other infrastructure. It is expected that climate changes, with more intense rainfall and increased temperatures, will contribute to an increase in landslide hazard (Gariano and Guzzetti, 2016; Hanssen-Bauer et al., 2017). It is estimated that every year about 200 of these events hit road sectors and about 30 hit railways (Hisdal et al., 2017). Norway has a long tradition of building physical structures (i.e. diversion dikes, tunnels, etc.) to protect road and railway lines in the most critical sites. Protection measures are still useful, but their maintenance is expensive and the building operations are time consuming. The climatic and topographic conditions in Norway indicate that it is an impossible task to provide 100 % protection of the national infrastructure. Therefore, forecasting and warning have become a crucial mitigation option to reduce risks.

Here we present the Norwegian Landslide Forecasting and Warning Service (known as “Jordskredvarslingen” in Norwegian). The service, or some of its components, has been partly presented and described in conference proceedings and previous articles (i.e. Devoli et al., 2014; Boje et al., 2014a; Bell et al., 2014; Piciullo et al., 2017). The service, presented herein, can be categorized as a “territorial” EWS following Calvello (2017) and as “forecasting and warning type” based on Stähli et al. (2015). The service is designed to predict the level of danger of rainfall- and snowmelt-induced landslides. The service predicts multiple landslides at national scale, in particular over a region (which is commonly an administrative county or a group of municipalities) on a regular basis (every day). As for the majority of territorial systems described in Calvello (2017) and Piciullo et al. (2018), the Norwegian one, presented herein, is also managed by a governmental institution that uses warning dissemination tools to warn multiple weather-induced hazards, including floods and snow avalanches. The service uses specialists to analyse meteorological and hydrogeological models and forecasts, sensor data, and predefined national and regional thresholds. Finally, the regional danger level is widely communicated through a bulletin.

The Norwegian Water Resources and Energy Directorate (NVE) is a directorate under the Ministry of Petroleum and Energy and is responsible for the administration of Norway's water and energy resources and the coordination of national efforts for landslide and snow avalanche risk prevention. NVE operates three forecasting services (landslide, flood, and snow avalanche) and several local warning systems for large rockslides (Engeset, 2013; Blikra and Kristensen, 2013). NVE has run a national flood forecasting and warning service since 1989. Back in 2009, the directorate was given the responsibility of also initiating a national forecasting service for rainfall-induced landslides (white papers: Meld. St. 22, 2007–2008; Meld. St. 15, 2011–2012). Both services are part of a political effort to improve flood and landslide risk prevention.

The development of EWSs for landslides started in February 2010 based on suggestions in Colleuille and Engen (2009). The landslide forecasting service started an operational test phase in January 2012. This service was officially launched in October 2013 and is run in close cooperation with the National Flood Forecasting and Warning Service. Since then, the service has operated continuously at regional scale for mainland Norway. The service is developed as a joint initiative across public agencies between NVE, the Norwegian Meteorological Institute (MET), the Norwegian Public Road Administration (NPRA) and the Norwegian Rail Administration (Bane NOR).

This work summarized the efforts made in the last 5 years by NVE and collaborators to design, develop, and run a nationwide landslide forecasting and warning service in close synergy with the Norwegian Flood Forecasting and Warning Service. The main purpose of this article is to describe the recent development and main components of the service, also indicating how the service is organized and how daily assessments are performed. We present the evaluation of the accuracy of assessments and use a case study as an example. Finally we present some feedbacks from regional and local emergency authorities on the usefulness of this new service.

The mainland of Norway (Scandinavian Peninsula) covers an area of 324 000 km2, with more than 490 000 km of rivers and streams and around 250 000 lakes. The country has large climatic contrasts, from maritime to continental climate, because of rugged topography that causes large local differences. The average annual precipitation is about 1400 mm, of which about one-third is snow. The precipitation distribution is non-uniform. In Western Norway, annual precipitation may exceed 5000 mm and daily values of 70 mm are not uncommon. In the east, some valleys annually receive less than 300 mm. The Fennoscandian Shield constitutes the Precambrian bedrock of Scandinavia. The oldest rocks, dating back 2.5 billion years, can be found in Northern Norway. Above the bedrock lie remnants of the Caledonian mountain range, while the youngest rocks are to be found in the Oslo Rift and provide evidence of volcanic activity 250–300 million years ago (Solli and Nordgulen, 2006). During the Quaternary, ice sheets covered Scandinavia several times. This resulted in poorly weathered but fractured bedrock without primary porosity, and young, sparse and thin sedimentary deposits. The aquifers in Norway mainly consist of (a) small, highly permeable glaciofluvial aquifers along streams and lakes, (b) small precipitation-fed tills in mountainous areas and (c) overlying fractured bedrocks without primary porosity, such as crystalline and metamorphosed hard rocks. The tills have limited storage capacity and groundwater responds fast to water input (rain and snowmelt). There are very few large and slowly responding groundwater reservoirs in Norway. A recharge–discharge mechanism determined by the physiographic and climatic conditions controls the groundwater level (Colleuille et al., 2007). In winter, precipitation falls as snow and the ground may freeze. This leads to a decrease in groundwater levels and increase in soil water storage capacity and contributes to surface runoff in streams and rivers. Following soil thaw and snowmelt in spring, groundwater levels rise rapidly.

Major natural hazards in Norway are extreme weather (wind storm, intense rainfalls), floods and different types of mass movements. Rock fall, rock slides, rock avalanches, mountain deformations (with a tsunamigenic potential), debris avalanches, debris flows, debris slides, rotational clay slides, and quick-clay slides are the most frequent landslide types in Norway (NVE, 2011). Different types of snow avalanches can be observed and slushflows are also common rapid mass movements (Fig. 1a–d).

The main flood types in Norway are rain flood, flood due to snowmelt, the combination of rainfall- and snowmelt-induced flood, and flash flood due to intense rainfall, the last of which especially in summer (Fig. 1e–g). It is the combination of rainfall- and snowmelt-induced flood that historically results in the largest floods in Norway, both in return periods and extent (e.g. south-eastern Norway, in 1995 and 2013). In coastal areas rain flood in autumn usually results the largest floods. This especially is the case for Western Norway and Northern Norway. In some glacial valleys, jøkulhlaup (glacier lake outburst flood) is a reoccurring and potentially dangerous event. Flood due to sudden release of water in ice dammed rivers, and flooding of riverbanks due to ice dames, are also a phenomenon well known in Norway, both during mild periods in winter and in springtime (Roald, 2013).

Rainfall- and snowmelt-induced landslides are triggered by water. Intense or long-duration water supply, caused by rain and/or snowmelt, increases the water content in the soil or snow. The cohesiveness of soil or snow particles decreases with higher water content, increasing the risk for mass transportation. Not only steep natural slopes covered by loose Quaternary sediments but also gentle slopes covered by snow as well as modified slopes and filling along roads and railways are especially exposed to these kinds of hazards. Climate scenarios for Norway indicate an increased occurrence of extreme weather, and intense precipitation is also expected to increase especially in the coastal areas of Norway (MET, 2013). Higher temperatures have led to earlier spring floods, and there is a tendency to increased frequency of rain floods. Future projections show that rain flood magnitude will increase, while snowmelt floods will decrease over time. More frequent and stronger intense rainfall events may in the future create specific challenges in small, steep rivers and in urban areas. Weather conditions are main triggers of certain types of landslides and snow avalanches; therefore changes in climate may affect their future frequency. The risk of slushflows will increase and may occur in areas where they have not occurred previously (Hanssen-Bauer et al., 2017).

The experience acquired from landslide events in Norway since 2011 shows that they can occur all year round. Important and recent landslides events are presented in Table 2.

There are limited comprehensive estimates of human and economic losses associated with natural hazards in Norway (e.g. floods and mass movements). In terms of fatalities, about 2000 persons have lost their lives in the past 150 years because of mass movements. Most of these casualties have been due to snow avalanches (Nadim et al., 2008). For landslides in soil, Aaheim et al. (2010) reported that 100 people have died since 1900 and most of the casualties are related to clay slides and quick-clay slides, often triggered by anthropogenic factors. Few data are available for casualties related to rainfall- and snowmelt-induced landslides. An effort to document fatalities associated with these landslide types was done by NVE in 2016 as part of the work presented in Haque et al. (2017) where landslides fatalities have been presented for the whole o Europe. For Norway the analysis showed that 42 people died in the period 1995–2016 due to 25 landslide events in the category of debris flows, debris avalanches, clay slides, quick-clay slides, rock falls, rock avalanches, and slushflows. The results indicated that 2005 and 2010 were the years with most recorded fatalities (ca. six persons). Most of the fatalities were caused by rock falls and rock avalanches, 7 because of clay-type slides, while 12 people died because of rainfall- and snowmelt-induced landslides (of these 7 due to slushflows and 5 due to both debris flows and debris avalanches).

In terms of economic losses, there are no reliable estimates of the total cost to society due to natural hazards, although insurance payments can provide an indication of cost trends. Payments made by insurance companies in Norway between 1980 and 2014 show both an increase in numbers of damaging events and increase in number of total claims per year, reaching around NOK 2500 million (∼ EUR 275 million) in the flood and landslides event of June 2011 in south-eastern Norway. However these numbers are underestimated since they do not include events and costs associated with public infrastructure (NIFS, 2016).

The daily landslide hazard assessment is performed by a forecaster who uses forecasted thresholds, forecasted hydro-meteorological parameters, information from real-time observations, knowledge on historical events and regional susceptibility, and personal experience. The daily landslide assessment routine is summarized in Fig. 6 and includes the following phases:

weather forecast, also as input for the hydrological model;

The warning scale is applicable for both flood and landslide hazards and consists of four levels using the same concept as meteoalarm (http://www.meteoalarm.eu/). The different levels show the landslide hazard and the recommended awareness (Table 3), providing information on what is expected to occur, the severity (qualitative estimation of numbers and dimensions of landslides) and recommended actions that the users should undertake or which measures should be initiated in order to reduce potential damages (Fig. 7).

The principle behind the awareness levels is that the highest level (red) occurs very rarely, while the second lowest level (yellow) occurs more often. Just for comparison, the red level corresponds to a flood with a return period of more than 50 years, while the yellow level corresponds to a flood with a return period of 2–5 years.

Emergency response authorities should be prepared to implement emergency plans, considering available resources, implementing preventive measures, safeguarding exposed assets, and carrying out evacuations and other contingency responses. One of the mitigation measures recommended is to ensure unhindered water channels, e.g. that culverts are not obstructed by ice, snow, sediments or other matter.

Golnaraghi (2005) and UN/ISDR (2006) expressed that “one of the most effective measures for disaster preparedness is a well-functioning early warning system that delivers accurate information dependably and on-time”. Therefore a useful EWS is the one capable of issuing correct warning messages which are easily understood and provided early enough to lead municipalities and contingency planners, emergency authorities to action in order to avoid or reduce damages due to landslides. This implies that a successful service requires periodically assessments of the technical performance and user perception (Devoli et al., 2017). In our service, we evaluate the so-called technical performance and the user perception.

Southern Norway is the area that includes the counties of Rogaland and Agder (e.g. Vest-Agder and Aust-Agder). As indicated in Devoli and Dahl (2014) and later in Devoli et al. (2017) the region is characterized by predominant hills and low relief with gentle slopes (< 25∘ locally up to 45∘) along the coastlines, as well as moderate slopes to elevated hills (< 25∘, but locally 25–45∘) in the interior. Alpine relief and steep slopes are observed in the valleys oriented in a N–S direction. The area is covered with tills, but along the coast and in the alluvial plains the soil coverage is thicker, with fluvial deposits, used for agriculture. In the eastern parts of Agder, near the coastline, there are also marine deposits.

For landslide forecasters these areas have been challenging since the start of the operations. The region is known to be an area with few landslide records, even though the area may receive large amounts of rain in autumn and sometimes in summer and winter. Along the coastline a few debris slides and some soil slides in artificial slopes have been registered in the database (https://www.skredregistrering.no). Many of these records had few details (i.e. unknown landslide type, day of occurrence, etc.), and many slides were not triggered by natural causes (i.e. rainfall/snowmelt) and occurred in days without rainfall, possibly triggered by anthropogenic factors. In the interior of the region, records of debris flows and debris slides are almost absent, and the few ones present have poor quality and are very uncertain. The lack of landslide records is also due to the low population density and transportation lines. From the experience acquired in the last 5 years and evidenced by the warning performance evaluations realized so far (see Sect. 5) it was clear that the thresholds were too high for the area. In 2016–2017 we reviewed the thresholds and tuned and updated them based on a few recent but most reliable events (Boje, 2017) (Fig. 2b).

At the end of September and beginning of October 2017 two powerful low-pressure systems, located initially north of Newfoundland, brought intense rainfalls over 3–4 days starting on 29 September 2017. The first low-pressure system was supposed to hit the western sector of the region, while the second, which also carried the remnants of the tropical cyclones Maria and Lee (http://www.noaa.gov), was supposed to hit the eastern part of the region, including also the Telemark county and some of the counties in southeastern sector of Norway. MET released a meteorological warning for the region based on available forecasts. Flood and landslide warnings were issued by NVE (Table 6).

The flood forecasting issued a warning at yellow level for Saturday 30 September on Thursday 28 September. On Friday 29 September the flood warning was elevated to orange for the 30 September. On Saturday 30 September the flood warning level was set to red, which stayed on red level for most of the Agder counties for 3 days, followed by an orange day (3 October) and one day yellow (4 October) before the river discharge returned to normal (Table 6).

The landslides thresholds for the area showed high awareness level in Agder, for a period of 2–3 days. The rail and road authorities had already been warned on Thursday 28 in an e-mail, before the first warning was issued. The rail and road authorities use this early information as an important input for the consideration of their contingency level and to initiate mitigation measures such as planning the possible closure of railways and the use of extra personnel.

The first issued warning, on Friday 29 September, was a yellow level for the days of Saturday 30 September and Sunday 1 October (Table 6). On Saturday 30 September, the level for landslide hazard was upgraded to orange and kept at orange for the two following days for parts of the Agder counties, while the rest of the area, including also the county of Telemark, had a yellow level (Fig. 8; Table 6). The hazard level for Telemark was reduced to green on Monday 2 October, but Rogaland remained at a yellow level for one day longer than the Agder counties, until 3 October. Based on these warnings the regional offices of NVE started to interact with the respective counties and municipalities to consider implementation of the emergency plans and to discuss the risk of damage.

During these rainfall events, which lasted from 29 September to 3 October, some of the rain gauges in the area (the Agder counties) received nearly 300 mm in 3–4 days. Many rain gauges measured precipitation that corresponds to rain from a more than 100-year return period (Gislefoss et al., 2017).

The first intense rainfall started around midnight on 29 September along the coastline of Rogaland, moving eastward through Agder counties the following hours. Most of the rainfall fell on 30 September and 1 October until 04:00. After a break during the day of 1 October, the second strong low-pressure system arrived in the evening of 1 October around 22:00, and the most intense rainfall fell until very early in the morning of 2 October (07:00–08:00).

These rainfall events triggered extensive floods and many landslides (Fig. 9) mainly in the counties of Vest-Agder and Aust-Agder, but some landslides occurred also in Rogaland and Telemark. In total, 80 % of the damages were to private buildings and many people had to evacuate. More than 3300 cases of damages were reported, for a total value of NOK 500 million (EUR ∼ 50 million) (Holmqvist and Langsholt, 2017).

The observed return period of flood was between 50 and 100 years in many of the large rivers of Agder. However, in some other rivers, the flood had even longer return periods. In the river Mandalelva, for instance, the flood was the highest registered since 1896. For many of the stations in this region, with long time series, this was the largest flood ever recorded (Holmqvist and Langsholt, 2017) (Figs. 9a, 10).

A preliminary registration (the verification is still in progress) shows that around 60 landslides events occurred between 29 September and 2 October in the counties of Rogaland, Agder, and Telemark. They were reported along the main roads, causing blockage, but houses were also directly affected. The landslides registered were mainly shallow soil slides and planar slides but also rotational and planar slides in clay materials, mainly of marine origin (Fig. 9b). NVE's regional engineers were attending several of the landslide sites. Because of the presence of marine clay deposits in this area, one of the main concerns was the fear that some of the small soil slides could develop into quick-clay slides. Most of landslides occurred during the most intense rainfall, during 30 October and during the night between 1 and 2 October.

The newly updated landslide thresholds for southernmost part of Norway, included Agder counties (Fig. 2b), proved very useful in this situation. This made the forecasters more confident that the high awareness level was necessary. However, since this event was the first in the area after the correction of the thresholds, we did not have experience with the new thresholds, which made the hazard assessment more complicated (Fig. 11). Daily communication between the regional NVE engineers on site and the landslide forecaster on duty helped to understand the ground conditions at local scale.

Due to the issued landslide and flood warnings the public and municipalities became more aware of the severity of the situation, before and during the event. Therefore they were more prepared to face damages and for closing of roads and railways.

The development of the rainfall- and snowmelt-induced landslide forecasting and warning service in Norway was possible thanks to a joint initiative across governmental agencies, and due to the fact that we could take advantage of existing IT tools, hydrological models and a hydrogeological network available at NVE as part of the well-established flood forecasting service.

The joint initiative with the MET, NPRA, and Bane NOR was crucial for the establishment of the service and it is still important for the operation of the service (in terms of economy, collection of landslide events, common research and development). The synergy with the flood warning service was significant for a rapid establishment and a rational operation (organization, hydrological monitoring and models, automatic collection of MET observations and forecasts, decision tools, warning routines and communication).

The Norwegian landslide forecasting and warning service uses real-time measurements of hydro-meteorological data (i.e. discharge, groundwater level, soil water content and soil temperature, snow water equivalent, meteorological data) and model simulations of the meteorological and hydrological conditions. The thresholds used are based on statistical analyses of historical landslides and simulated hydro-meteorological variables (such as rainfall, snowmelt, soil saturation, and depth of frozen ground) and shown as a hydro-meteorological index. The service identifies potentially dangerous situations and notifies local emergency authorities and the public up to 66 h ahead with the purpose that they can take preventive measures. A case study from autumn 2017 has been presented showing how the service is well functioning and useful in order to prevent and reduce damages due to landslides and to save lives.

The first results after 4 years of operations indicate that the flood and landslide services have succeeded as a tool for the road and railway authorities in increasing awareness, preparedness, and risk reduction. NVE's user survey from 2016/2017 (Epinion AS, 2017) confirms that warnings issued by NVE (flood, landslide, snow avalanche) is considered as an “alarm clock” for the municipalities and contingency planners. The service is wanted and appreciated by our most important users, mainly those responsible for emergency response at municipalities and counties, as well as the police.

Our aim and strategy is to provide correct forecasts of both spatial and temporal landslide occurrence and systematically updated landslide bulletins. Therefore, we need

reliable weather forecasts;

Even if the service is quite satisfactory, there are still many challenges and limitations. The hazard assessment, tools for decision making (xGeo, hydrological models, indexes and thresholds) and communication (http://www.varsom.no/) need continuous development and improvement. To improve the accuracy, precision and usefulness of the service, the following areas should be strengthened.

Hazard assessment. The usefulness of the issued warning can be increased considerably by combining landslide hazard and vulnerability data. Therefore hazard and risk maps represent important tools for local authorities that assist them in setting priorities and where to implement the required measures. However, hazard maps and risk maps are not available in the Norwegian municipalities; therefore landslide susceptibility maps available for the entire country could be used by local emergency authorities. These maps have been used to improve the thresholds, but they could support the municipalities by showing where landslides may occur. We need to communicate better the importance of such maps to the users, from a lack of other hazard maps.

Weather forecasts and hydrological models. Reliable warnings require reliable meteorological observations and forecasts. It is still challenging to predict landslides triggered by summer rain showers. The cooperation between MET and NVE has contributed to improved grid data (precipitation and temperature) of observations and forecasts, thus improving estimates of snow, water flow, and other hydro-meteorological variables.

The hydrological model used to calculate the water saturation, a parameter used in landslide thresholds, still has a rough resolution in both time (24 h) and space. The model uses input grid data of precipitation and temperature (observations and forecasts) based on a rough interpolation and does not yet utilize the improved grid data provided by MET at the end of 2016 (Saloranta, 2016; Lussana et al., 2018). An improved version of the model is scheduled to be operative in 2018/2019. It is also appropriate to implement 3 h resolution. Therefore, there is still considerable potential for improving the basis used for landslide thresholds.

Better verification of landslide events. The service requires reliable data of landslide events (e.g. correct type, date, place, triggering). This is a prerequisite both for establishment of thresholds and for post-evaluation. For the first evaluation, it is enough to know if landslides have occurred, but to tune the warning levels it is important to know how many landslides occurred under a specific warning level. It is essential to have a good overview of the number and dimension of landslide events that occurred after a rainfall and/or snowmelt episode. NVE maintain a national database; however, the registration is still sparse; i.e. there is no systematic record of events in all regions of Norway. The quality of registrations also varies greatly. There is no consistency in data collection and there are problems with the classification of different landslide types. Release time and location can also be wrong and triggering causes not reported.

A major issue for the verification of the landslide occurrence is that we rely on media and not on systematic field observations. For events on buildings or outside main roads and railways, the data collection is sparse compared to registrations of landslides close to roads and railways.

Upgrading of landslide inventories is mandatory after each forecast in order to have the correct type but also number and dimensions of landslide events.

In Norway most of the data along roads (which is the majority of events) are not recorded by specialists, and hence there is a degree of uncertainty in the quality of the data. The NPRA is now working to ensure that all contractors responsible for driving roads use a standard format and receive periodic training. Because of the poor quality of landslide data and lack of observations, it has been a challenge to tune the landslide thresholds in some regions.

Increase communication and build the user's capacity. The greatest opportunity to increase the benefit of the service is to build expertise among users. Some of the challenges are communicating the warning on time and with sufficient leading time to take actions and the communication of the uncertainty. We have observed that rainfall- and snowmelt-induced landslides are often considered as flood damages (i.e. debris flows and debris slides/avalanches) or snow avalanche damages (i.e. slushflows). There is a need to strengthen the dissemination work specifically aimed at regional and local authorities, as well as the public and the media, so that the warning service itself, the background for alerts and the different landslide types are better understood. The goal is also to get users and recipients of warnings to contribute significantly more, for example registration of hazard signs and landslide events.