Henry’s Fork, January 17th, 2023
Headlines From Dr. Rob Van Kirk’s SWE Report of Yesterday for the Henry’s Fork Drainage.
- Thanks to a solid storm over the weekend, precipitation last week was above average, keeping the water-year total at 110% of average and increasing SWE to 115% of average.
- Generally dry conditions with below-average temperatures are expected for the next two weeks. New snow water equivalent (SWE) was 19% above average for the 8-day period, ranging from 1.4 inches at Phillips Bench (Teton Pass) and Grassy Lake to 3.0 inches at Grand Targhee. Current SWE is 115% of average: 104% in Teton River, 107% in Fall River, and 129% in upper Henry’s Fork. Upper-level atmospheric flow has shifted from southwest to northwest, finally putting an end to three weeks of continuous heavy precipitation in California. For us, the change means cooler-than-average temperatures and generally dry conditions for the next week or two. If that forecast proves to be correct, water-year precipitation here will drop relative to average over the next week to around 107% of average, and SWE will drop to 105% of average.
- At an outflow of 201 cfs, Island Park Reservoir is 75% full, compared with 73% full on average.
- Combined volume in the three reservoirs in the watershed caught up to average yesterday, at 79% full.
Rob Van Kirk, Ph.D.
Senior Scientist
P.O. Box 550
Ashton, ID 83420
208-881-3407 CELL