Henry’s Fork, December 20th, 2022
Here are details from Dr. Rob Van Kirk’s SWE report this AM for the Henry’s Fork drainage.
Note the waning he gives for weather conditions the next several days.
Mean temperature yesterday was 5 degrees F below average. Only very light precipitation was recorded, dropping the water-year total to 109% of average and snow water equivalent (SWE) to 117% of average. The latest precipitation forecasts are a little wetter than yesterday’s, now calling for up to 2 inches of water equivalent along the Teton crest from today through next Monday. Potentially heavy snow remains possible early next week.
In the meantime–for those who live or are considering traveling here over the next few days–an extremely strong cold front is expected to pass through the area tonight and early tomorrow morning, bringing 40+ mph winds and widespread blowing snow. Following the front, temperatures will drop well below zero on Thursday morning. If forecasts hold, the upcoming cold temperatures will be the lowest we have seen since December 2016. Travel is not advised and will not even be possible in some places tomorrow and Thursday.
Where stream gages are still reporting, natural flow is still in the 70-75% of average range, where it has been since September.
At an average outflow of 193 cfs, Island Park gained 309 ac-ft yesterday, staying well ahead of the fill rate needed to meet the reservoir volume target at ice-off, which occurs in late April on average. The reservoir is 68% full, only 376 ac-ft below average.
Rob Van Kirk, Ph.D.
Senior Scientist
P.O. Box 550
Ashton, ID 83420
208-881-3407 CELL
208-652-3568 FAX