Item: A CLIMATOLOGY OF RAIN-ON-SNOW EVENTS IN SVALBARD AND THEIR IMPLICATIONS FOR AVALANCHE HAZARD
-
-
Title: A CLIMATOLOGY OF RAIN-ON-SNOW EVENTS IN SVALBARD AND THEIR IMPLICATIONS FOR AVALANCHE HAZARD
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- HANNAH VICKERS [ NORCE ]
- JAKOB GRAHN [ NORCE ]
- EIRIK MALNES [ NORCE ]
- PRISCILLA MOONEY [ NORCE ]
Date: 2024-09-23
Abstract: Rain-on-snow (ROS) events have become increasingly common in the wintertime across the Arctic as its climate continues to warm at an alarming pace. It is projected that Svalbard will experience a threefold increase in the frequency of winter warming events by 2100 with profound impacts on land and glaciers. Changes in the frequency, intensity, duration and spatial distribution of ROS are important to quantify due to their wide-ranging impacts on the physical environment and on society, which included increased avalanche risk, permafrost degradation, damage to vegetation and difficult foraging conditions for reindeer as ground ice forms following a ROS event. To understand which areas are most vulnerable to ROS impacts at present and in the future, reliable datasets describing the spatial and temporal variations of ROS are crucial. We have used Synthetic Aperture Radar (SAR), which is sensitive to liquid water in the snowpack, to map ROS events for the period 2004-2020. The results are compared against ROS events detected using a reanalysis and snow model dataset, which had been calibrated against ground observations. The ROS climatology observed by SAR and reanalysis data were in general consistent with each other, showing that ROS occurs most frequently in the southern and western parts of Spitsbergen and very few, if any, occurrences across the glaciated areas and northeastern parts. We have also estimated the intensity, duration and timing of the ROS events since 1991, and their trends. Significant increases in the frequency, intensity and duration of ROS events were found, with no parts of the archipelago exhibiting a significant decrease in any characteristic. Lastly, since SAR is also sensitive to changes in snow surface roughness, avalanche debris can be detected using a change detection approach. We present an overview of a recently published SAR dataset for avalanche activity for Svalbard for the period and show that SAR detects an increase in avalanche activity increases during ROS events. Climate projections may provide an indication of how the spatiotemporal characteristics of ROS events will change in the future, and therefore how wet snow avalanche activity may be affected as a result.
Object ID: ISSW2024_P9.7.pdf
Language of Article: English
Presenter(s): HANNAH VICKERS
Keywords: Svalbard, rain-on-snow, avalanche hazard, climate change
Page Number(s): 1284 - 1291
-