Changes of hydro-meteorological trigger conditions for debris flows in a future alpine climate

• Published in: The Science of the total environment 2023-05, Vol.872, p.162227-162227, Article 162227
• Main Authors: Kaitna, Roland, Prenner, David, Switanek, Matt, Maraun, Douglas, Stoffel, Markus, Hrachowitz, Markus
• Format: Article
• Language: English
• Subjects: climate; Climate change; Debris-flow initiation; environment; Hydrological modeling; hydrometeorology; rain; risk management; snowmelt; storms; Trigger conditions
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.162227

Debris-flow activity is strongly controlled by hydro-meteorological trigger conditions, which are expected to change in a future climate. In this study we connect a regional hydro-meteorological susceptibility model for debris flows with climate projections until 2100 to assess changes of the frequency of critical trigger conditions for different trigger types (long-lasting rainfall, short-duration storm, snow-melt, rain-on-snow) in six regions in the Austrian Alps. We find limited annual changes of the number of days critical for debris-flow initiation when averaged over all regions, but distinct changes when separating between hydro-meteorological trigger types and study region. Changes become more evident at the monthly/seasonal scale, with a general trend of critical debris-flow trigger conditions earlier in the year. The outcomes of this study serve as a basis for the development of adaption strategies for future risk management. [Display omitted] •Climate change alters the hydro-meteorological trigger patterns for debris-flow initiation in the Austrian Alps.•Changes are regionally different.•Trend to occur earlier in the year.•Snow-melt related triggers may become more frequent.