Flood loss modelling is subject to large uncertainty that is often neglected. Most models are deterministic, and large disparities exist among them. Adopting a single model may lead to inaccurate loss estimates and sub-optimal decision-making. This paper proposes the use of multi-model ensembles to address such issues. We demonstrate that this can be a simple and pragmatic approach to obtain more accurate loss estimates and reliable probability distributions of model uncertainty.

We study flood protection options in a pre-alpine catchment in southern Germany. Protection systems are evaluated probabilistically, taking into account climatic and other uncertainties as well as the possibility of future adjustments. Despite large uncertainty in damage, cost, and climate, we arrive at a rough recommendation. Hence, one can make good decisions under large uncertainty. The results also show it is preferable to plan risk-based rather than protecting from a specific design flood.

This paper studies the lake dynamics for avalanche-triggered glacial lake outburst floods (GLOFs) in the Cordillera Blanca mountain range in Ancash, Peru. Lake Palcacocha is used as a case study to analyze the upper watershed processes that typically comprise a GLOF event, specifically the lake dynamics when an avalanche produces a large displacement wave that might overtop and erode the lake-damming moraine.

Debris flow early warning has always been based on well-calibrated rainfall thresholds. For areas where historical data are insufficient, to determine a rainfall threshold, it is necessary to develop a method to obtain the threshold by using limited data. A quantitative method, a new way to calculate the rainfall threshold, is developed in this study, which combines the initiation mechanism of hydraulic-driven debris flow with the runoff yield and concentration laws of the watershed.

Coastal and submarine landslides occur on average every 30–50 years at the western tip of the Gulf of Corinth. These landslides trigger tsunamis and thus represent a significant hazard. We realized an inventory of the submarine landslide deposits in the western Gulf. Six large events are identified in the last 130 000 years. Such sliding events likely generated large tsunami waves in the whole Gulf of Corinth, possibly larger than those reported in historical sources.

Norway has, since 2013, an operative nation-wide landslide forecasting and early warning system for shallow landslides. The early warning system uses thresholds for soil moisture and water supply from rain and snowmelt to issue warnings to the public and relevant authorities when the risk for landslide hazard is present. The warnings are regional and are issued at www.varsom.no. Colours are used to symbolize the hazard level.

Recent tsunami events have exposed the need for further work to develop and apply tsunami risk reduction measures. A key parameter that must be adequately determined is the run-up, the maximum elevation to which water from a tsunami wave will rise during its flooding process. In this work, a new methodology to simply calculate the run-up is presented. The methodology has been applied to calculate a tsunami run-up database, where the run-up of new events can be calculated by interpolation.

We present a multiscale and multi-sensor methodology for flood mapping using free or low-cost data. We first mapped flooded areas at basin scale using free satellite data using both SAR and multispectral sensors. At local scale we refine mapping using very high-resolution images from Remotely Piloted Aerial System and terrestrial car camera, then we used these data to create 3-D model with structure from motion (SfM). All these data allowed creating accurate flooded area and water depth maps.

This article describes the first volcanic emission advection model based on an adaptive mesh. The advection of volcanic emissions plays a crucial role in climate research, air traffic control and human wellbeing. In contrast to already existing volcanic emission dispersion models relying on a fixed grid, the application of an adaptive mesh enables us to simulate the advection of volcanic emissions with a high local resolution while minimizing computational cost.