RHyCAMLab · University of Oklahoma

Discoveries / Research story · Nature Climate Change, 13 (2023)

The wettest winter storms in the western U.S. are getting sharper

By mid-century, the strongest cold-season storms could bring up to 40% more precipitation, concentrated toward their centers — with direct consequences for how infrastructure is designed

The question

Winter storms in the western U.S. cause billions of dollars in damages. How will the precipitation they deliver — and how it is distributed within each storm — change as the climate warms?

Key findings

  1. By mid-century, the strongest winter storms could bring up to 40% more precipitation.
  2. The increase is not uniform: more precipitation falls near the storm centers, so storms become spatially “sharper”.
  3. If these structural changes are not accounted for, infrastructure planning could misjudge future storm risks.
Illustration of a storm whose precipitation is concentrated over a watershed with a dam
Schematic of a sharpening cold-season storm over a mountain watershed.

Engineers size dams, spillways, and drainage systems using the precipitation a storm deposits over a watershed. That depends not only on how much falls in total, but also on how it is distributed in space and time. This study looked at both, treating each cold-season storm as an object with its own footprint and internal structure.