Disclaimer: You are responsible for planning your hike and preparing yourself. This is only a prediction and is only meant to be one of many tools at your disposal for planning your trip.
Has the snow depth peaked?
Here I am assuming it has. The snowpack for the entire Cascade Crest peaked on the same day across the entire state - on April 1st.
My assumption here could be very wrong. We often get more snow after May 1st, like in 2022, 2012, and 2011. Even last year we had additional snow accumulation on May 24th and June 7th.
What is the distribution of the snowpack across the trail?
This year the snowpack on the trail is deeper in the south and thinner in the north, with a difference of about 40". That is typical. But keep in mind that, on average, the trail is lower in the south and higher in the north. So often the entire trail emerges from the snow in the same week. Note that snow depth along the trail is different from snow depth along the crest. The trail north of Suiattle Pass is in a snow shadow. and Indian Heaven in the south gets concentrated precipitation.
In past years I've tracked all the snow depth sensors near the PCT, but I've learned that watching any sensor below 4,000 ft is kind of a waste of time for this purpose. So I only track the UHF sensors at higher altitudes.
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Harts Pass (6,490 ft) mm 2625 - peaked at 79" and is melting at an average rate. (now 58", 81% of average).
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Lyman Lake (5,980) mm 2555 - peaked at 118" and is melting slightly faster than average. (now 88", 58% of average).
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Green Valley (6,230) mm 2335 - peaked at 101" (Rainier effect) (now 83", 78% of average).
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Chinook Pass Base (5500) mm 2327 - peaked at 176" (now 149", 92% of average).
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White Pass Upper (5,800) mm 2294 - peaked at 119" and is melting much faster than average. (now 94", 97% of average).
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Surprise Lakes (4,290) mm 2218 - peaked at 117" and is melting slightly faster than average. (now 88", 96% of average).
These sensors, mounted high on poles, use UHF sonar reflection to measure the snow depth. Generally, these sensors accurately measure the melt rate, but often are not giving an accurate measure of total snow depth. That is because the zero calibration is sometimes off. You can see this in mid-summer when it consistently measures something other than zero until its recalibrated.
How long will it keep freezing at night?
This is the most important question of all.
For example, 2023 was an incredibly rapid melt because the temp never hit freezing at night that spring. But 2024 was a slow melt because the snowpack kept re-freezing every night. Ironically, the crazy heatwave in June 2021 did not do much to accelerate the melt. It seems to be more about just not re-freezing at night.
As shown above, all sensors show melt rates that are slightly faster than normal or much faster than normal. The 30-day forecast for May is for average temperatures and average precipitation. The three-month forecast for the area predicts above normal temperatures and below normal precipitation. In satellite photos the snow line appears higher than normal. So here I'm assuming an average melt rate in May and a slightly faster than average rate in June.
What does "snow free" mean?
I know backpackers like me are eager to get out there and hike but want to avoid carrying heavy traction and arrest gear. My goal is to identify a date when about 95% of the trail has emerged from the snow, thus significantly reducing the risk (but not eliminating the risk) of not carrying snow gear.
That day is not the day all the snow sensors read zero. All those snow sensors are in full sun all day long. What I’ve learned from tracking this year over year is that the snow on north facing slopes and forested valleys will take three more weeks to melt. And even then, there will be some snow patches on the trail.
PREDICTION
I think the trail will be 95% snow free by July 1st. This assumes the high route, not the low route, over Old Snowy Mountain will be snow free by then. I will revise this prediction on June 1st for more accuracy.
As it happens
As with last year, as sections begin to open up I will post a trail report every 5 days until 95% of the trail is exposed. trail report