Henry’s Fork, January 20th, 2024

Headlines from Dr. Rob Van Kirk’s Henry’s Fork Drainage Snow-Water Equivalent (SWE) Report of January 19th.

• Yesterday’s precipitation increased the water-year total to 88% of average and SWE to 69% of average but increased the disparity even more between the southern half of the watershed and the upper Henry’s Fork.
• Light but consistent precipitation will continue for the next week, with temperatures well above average.
• At an average outflow of 386 cfs, Island Park Reservoir gained 20 ac-ft yesterday and is 90% full, compared with 73% full on average.
• The upper Snake River reservoir system is 71% full, compared with 58% full on average.

Details

New snow water equivalent (SWE) totals ranged from 0.1 inch or less at all stations in the upper Henry’s Fork to 0.7 inches at Pine Creek Pass and Grand Targhee. That moved watershed mean SWE up one more percentage point to 69% of average, although it dropped a place in the rankings to 3rd driest since 1989, now behind 2012 but still ahead of 2001 and 2010. SWE at Pine Creek Pass improved to 95% of average, moving that in the Teton subwatershed up to 79% of average. SWE is 74% of average in Fall River and 57% of average in the upper Henry’s Fork, the lowest on record for the date.