Extreme Weather

Overview

Over the last 50 years, much of the U.S. has seen increases in prolonged periods of excessively high temperatures and an associated expansion of drought. This contributes to larger wildfires burning more acreage per incident, heavier downpours leading to torrential flooding, more intense winter weather events, stronger tropical storms, and a persistent increase in sea level rise across all coasts as baseline temperatures continue to rise.

These shifts from severe weather to more damaging events nation-wide has led to impacts across all 16 critical infrastructure sectors and a growing need to improve resiliency. Extreme weather events have become far more disruptive and destructive than ever recorded and are projected to steadily worsen.

CISA’s Role

It is CISA’s mission to ensure critical infrastructure is protected against extreme weather threats and events. Infrastructure built in the 1900s to early 2000s using climate data from the mid-1900s lacks the ability to withstand the changes occurring in both intensity and frequency of extreme weather events and could experience excessive damage or destruction.

CISA analyzes extreme weather and its impacts to critical infrastructure. We discuss potential increases in weather damages with infrastructure owners and operators, conduct exercises centered around damages from major weather events with stakeholders, and develop resiliency focus documents to outline practical guidelines and strategies for implementation.

CISA analyzes and shares current data trends and findings through:

• Open-Source weekly summaries on national-international climate studies, recent weather impacts, new research opportunities, and products focused on extreme weather.
• Presentations about national, regional, state, or infrastructure-related climate impacts and the cascading effects to physical infrastructure, site operations, and community resilience.
• Impact analyses of National Critical Functions.
  • CISA and the Homeland Security Operational Analysis Center (HSOAC) developed a risk management framework to assess the risk of extreme weather to higher vulnerability NCFs.
• Regional Resiliency Assessment Program (RRAP) reports addressing the impacts of extreme weather events to a sector or region for cascading impacts.
  • There are several ongoing and planned RRAPs with climate impact-related aspects, such as drought, sea level rise, and harmful algal blooms affecting water supply. 
• Factsheet to address extreme weather impacts to telecommunications.

CISA, through the Analytic Exchange Program (AEP), produced a website to further engagement with critical infrastructure owners and operators as well as communities across the nation by providing amplifying information on each of the eight worsening weather hazards, methods of identifying site-specific extreme weather forecasts, and federally backed climate resiliency options for consideration with associated funding opportunities from both government and private sector entities. 

• This website hosts numerous studies, factsheets, and resources from interagency partners and the scientific community, furthering CISA’s commitment to a whole-of-government approach to resiliency planning and coordination of mitigation efforts.

https://experience.arcgis.com/experience/a1ec0d1276064ae387c863f2a14b11e1/

Severe Weather vs. Extreme Weather

Severe weather is considered to be an intense variation of a regionally common weather event, such as a heavy rainfall event or damaging winds. Extreme weather identifies the trend of more severe weather events both in frequency and intensity, such as torrential rain (excessive rain periods where over one month of rain can fall during a single storm) or record-breaking peak gusts with widespread wind damage.

Extreme weather is the most intense climate element observed during a given period, typically longer lasting or more damaging than the historical ‘worst case’ events. Infrastructure is built to climatological norms for the 20-40 years prior to development, accounting for typical severe weather events experienced regionally but not planning for withstanding extreme weather events. As extreme weather events become more common, critical infrastructure sites will need to revisit building codes, material limitations, and regional damages during past severe events to address areas at greatest immediate risk.