Snow Melt Runoff on the Increase much of Western Wyoming Mountains

Hydrologic Outlook

National Weather Service Riverton WY
1055 AM MDT Wed May 31 2017

..Warm mountain temperatures Wednesday through Saturday
will accelerate snowmelt runoff...

...Flooding expected on smaller creeks and streams by the end of the
week with minor flooding along main stem rivers by the weekend...

Decreases of up to an inch of snow water equivalents (SWEs) occurred
at the 9,000 foot elevation in the last 24 hours at several SNOTEL
locations along the Green and Wind River Basin. There is still around 30
inches of SWEs at several SNOTEL locations at the 9,000 to 10,000
foot elevation across the Wind, Green, Shoshone, and Upper Yellowstone
Basins.

Afternoon temperatures at the 9,000 foot elevation are expected to
warm into the lower to middle 60s Wednesday through Saturday.
Morning low temperatures will also be above the frost
temperature of 37 degrees Wednesday through Saturday.
Windy conditions over the mountains are expected Thursday afternoon
through Friday morning. Mountain rain showers will be more widespread
Thursday afternoon through Friday morning.

Accelerated snowmelt runoff will cause sharp increases in stream and
river levels Thursday morning through Saturday morning. The greateat
increase in stream and creek levels will be Thursday evening through
Friday morning. Flooding of low lying areas is expected on smaller creeks
and streams by Friday; with minor flooding expected along main stem rivers
like the Green, Little Wind, Big Wind, Sweetwater, and Shoshone by
Saturday and Sunday.

People living near flood prone areas along creeks and rivers should make
final preparations for high water later this week through this weekend.
Mountain streams run the highest in the late afternoon through early evening
hours. Do not attempt to cross streams at that time as the swift water will
easily carry you downstream.

Look for flood watches and/or advisories to be issued Thursday and Friday

for the upcoming flooding event.

Graphical forecasts are available at:
http://water.weather.gov/ahps2/index.php?wfo=riw
Visit weather.gov/riverton and select the rivers & lakes tab for
graphical forecasts and additional information.