Wyoming Spring Runoff 2020 Flood Potential--issued April 8th

Heavy Rainfall to Bring Flooding Threat to California; Heavy Snow in the Sierra

A strong atmospheric river will bring heavy rainfall to California through the holiday week. The heaviest rainfall is expected on Wednesday in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall is expected in the Sierra Nevada from the atmospheric river, raising concerns for major snow‐load impacts. Travel may be difficult to impossible over the passes. Read More >

SYNOPSIS

Early April snowpack and/or SWEs were above average (105 to 115% of median) across almost all major basins in Wyoming.

Above average snow depths across far western Wyoming.

Average soil moisture percentages across basins in northeastern Wyoming and portions of the Wind River Basin; Below average soil moisture percentages across southern Wyoming.

Widespread pine bark beetle damage (2010 to 2018) across the Upper North Platte, Little Snake, Laramie, and Wind River Basins.

No significant precipitation trends during the spring runoff season (May – July). Above average temperatures are expected across central to western Wyoming during the runoff season.

HIGHLIGHTS

Low to Moderate potential for flooding due to spring snowmelt runoff across portions of the Salt River Basin (far western Wyoming) and portions of the Little Laramie River Basin. All other headwater basins will generally have a Low potential for snowmelt runoff flooding.

Latest Wyoming Spring Flood Potential graphic: