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Photo: Dave Hansen Whitewater

JACKSON, Wyo. — Spring has arrived and it’s time to start thinking about how this year’s snowpack will affect the upcoming whitewater rafting season. Read on to learn how winter snowpack, spring temperatures and the timing of snowmelt all influence the spring runoff. Enter to win a raft through Dave Hansen’s High Water Heyday Contest for a chance to win a new raft!

Currently, we can see that snowpack is close to average this year across the Snake River Basin based on snow-water equivalent measured hourly at numerous locations in the surrounding mountain ranges.

Peak winter snow depths relative to average

First, there is the obvious connection between peak snow depths and peak river levels. Typically, if the snowpack is above average, peak river levels will also be above average.

However, sometimes this is not always the case. In 2019, the snowpack was above average and peak river levels were below average. The explanation for the lower stream levels in 2019 is that temperatures were colder than average temperatures in May, which slowed the rate of snowmelt.

Spring temperatures relative to average (particularly in May)

Spring temperatures have a significant influence on snowmelt rates, which in turn influences river levels. Snowmelt rates are at their highest during the month of May, so temperatures relative to average during May are the most highly correlated to river levels.

WHEN snowpack reaches its maximum depth

The other key factor that influences river levels is when the mountain snowpack reaches its peak. Years when the snowpack reaches its peak before April 1 tend to result in lower river levels compared to years when snowpack peaks later.

Predicting the High Water Mark for 2022

The remaining question mark is what happens with temperatures over the next four to six weeks.

Using the above data, what do you think the high mark will be during 2022? Enter your guess for a chance to win a raft down below.