Overall, Idaho has had a wonderfully average snow year this season. The entire region is at a normal snow level when it comes to snow water equivalent. Eastern Idaho and Western Wyoming are all at or above 100 percent. There are some pockets of regions in Central and Western Idaho and Western Oregon that are slightly lower than normal. This is a long-winded way of saying we are expecting exceptional water here in Idaho.
This week up in the Warm River area, we have seen or are expecting wet weather. Daytime temperatures are in the 30s – 40’s, and it stays under 32 degrees at night. This brings mountain snows and rainy and slowly melting snow in the valleys.
In fact, from March 11 until March 18, the snow increased in Island Park by 4 to 5 inches. But over the last couple of weeks the snow has pretty much stayed at around 40 inches of snow depth in the Island Park area. Great news for runoff! Check out Snotel and see how runoff is going for yourself.
We highly rely on mountain snowpack to provide much-needed moisture throughout the spring and summer.
The denser and slower the snow melts, the better. Idaho has a lot of lakes and reservoirs to ‘help flatten the curve’ (see what I did there; ) of snow runoff. But, there is far more snow water equivalent vs. reservoir capacity. So the main job of reservoirs is for flood prevention, and second, irrigation for our farmers and ranchers.
The South Fork of the Snake River just increased flows to 5000 CFS at Irwin. More and more people have been fishing the South Fork and have been getting back with positive reports. Normally, fluctuation in flows disturbs the fish for a little bit. But they settle in pretty quickly. At this point in time, it’s more ambient temperatures and stream temperatures that we try to monitor.
The Henry’s Fork is one of the world’s largest spring creeks, so it’s a little bit more steady and stable for spring runoff when you compare it with the South Fork of the Snake, Madison River, or a few others in our area. Right now, the Henry’s Fork is slightly higher than average, but well within the 61-year median daily statistic.
Here are some realtime charts for the Owyhee River and the Boise River.