Extreme weather events can also influence the frequency, severity, and intensity of geohazards. For example, rising temperatures and melting permafrost can lead to loss of bearing capacity and structural damage due to differential settlements; droughts can cause lowering of groundwater, surface subsidence and cracking of structures. Longer drought periods can increase the frequency of wildfires, destroying stabilizing vegetation and increasing runoff and potential for debris flows.
Higher-intensity precipitation can exacerbate burn areas and lead to a higher risk of erosion, mudslides, landslides or rock falls. Factors affecting the severity of these major stressors to communities and the built environment include not only the proximity to the hazard itself (e.g., distance from coasts, mountains, valleys, active faults) and condition of the infrastructure assets or systems, but also the pre-event resilience and response planning.
Physical damage to infrastructure due to climate effects is accompanied by economic damage, increased potential for loss of life, and other impacts to the overall well-being of communities. Landslides in the U.S. alone are estimated to cost $2-$4 billion and cause 20 to 50 deaths annually.
Departments of transportation (DOTs) are proactively taking measures to face extreme events. In Oregon—where landslides are a common chronic problem that may be exacerbated by extreme events, such as during times of heavy precipitation or during earthquakes—the state DOT is developing and implementing more rigorous design standards, retrofitting prioritization plans, and making strategic partnerships to improve rapid response and recovery. For critical lifelines and corridors, hardening and triage plans are predicted to save 5,000 lives during a large seismic event and ensure prompt return to business as usual, illustrating the importance of preparing for extreme events.