Henry’s Fork, November 9th, 2021
Streamers and nymph patterns are the ” Name of the Game” up and down the river now.
All of us are interested in what upcoming winter snowfall and water situations will be for the Henry’s Fork drainage. Such information can provide likely water conditions during the next angling season. Thus we will continue reporting what information Dr Rob Van Kirk assembles each week on the drainage water conditions. Information Rob offers from his Monday,November 8th report follows.
Headlines:
- Yesterday’s mean temperature was the coldest since March 31, and some precipitation lingering from the weekend was recorded very early yesterday morning.
- Natural flow has dropped a little over the past day or two to 73% of average for the date.
- At a mean outflow of 120 cfs, Island Park Reservoir gained 473 ac-ft yesterday and is 60% full, compared with 57% full on average.
- Above-average temperatures and near- to above-average precipitation are expected to continue.
Details:
Yesterday’s mean temperature was the lowest since March 31, although it wasn’t even all that cold, at 3 degrees F below average. A little precipitation leftover from Sunday was recorded very early yesterday morning at a few locations in the northern and eastern areas of the watershed. Snow accumulation so far this fall remains below average, despite above-average precipitation. At least for now, the combination of warm temperatures and above-average precipitation is favorable to increase soil moisture prior to the inevitable arrival of widespread freezing temperatures and snow accumulation. In general, temperatures are expected to remain at or above average, and near- to above-average precipitation is also expected to continue.
Watershed-total natural flow has dropped a little over the past day or two and is 73% of average for the date and 75% of average for the water year so far.
At an average outflow of 120 cfs, Island Park Reservoir gained only 473 ac-ft yesterday on a day without precipitation. Over the weekend, a substantial fraction of reservoir fill was due to direct precipitation on the reservoir. Precipitation forecast over the next week will add around 250 ac-ft over and above that due to stream inflow. The reservoir is 60% full, compared with 57% full on average.
G
Rob Van Kirk, Ph.D.
Senior Scientist
P.O. Box 550
Ashton, ID 83420
208-652-3567 OFFICE
208-881-3407 CELL
208-652-3568 FAX