Mt. Rainier – Disappointment Cleaver

The storm timing is the controlling factor on this trip. Tuesday looks genuinely clean — partly sunny, winds 0-6 mph at the surface, near-freezing temps, and only 8% precip chance. At summit elevation (~14,411 ft), expect surface winds to roughly double, so call it 10-12 mph at the crater rim — workable. Overnight Tuesday into Wednesday is still partly clear with 5% precip and surface winds at 3 mph NW. That's your window. Wednesday afternoon is when it breaks down: 58% precip chance with light snow likely, degrading to 98% and active light snow Wednesday night with winds building to 13 mph SW at the surface — translate that to 20-25 mph at the summit with blowing snow and deteriorating visibility. If you're not off the upper mountain by Wednesday noon, you're in it.

The snowpack data is minimal. SNOTEL at Annie Springs (6,021 ft) shows 0 inches of snow depth with only 0.2 inches SWE, and the lower stations show nothing — this is a bare-ground, early-season situation below treeline. The Northwest Avalanche Center has issued no rating for the West Slopes South zone, which reflects the pre-season state rather than a clean, stable snowpack. The bulletin's own language flags it: watch for signs of instability — cracking, collapsing, recent slides. Whatever snow exists on the upper mountain is likely an early-season accumulation without a well-developed stratigraphy. Treat any snow-covered steep terrain with suspicion, especially on the DC route above 10,000 ft where early-season wind effect and poorly bonded snow can produce unexpected instability.

Freezing level is sitting right around 3,000-4,000 ft given surface temps of 29-39°F at the forecast grid. That means the entire route above Camp Muir (~10,080 ft) is well below freezing — expect consolidated ice and firm névé on the Cleaver itself, which is good for crampons but means no softening to bail you out on hard moves. The Wednesday storm precip type will be snow at all elevations given temps in the upper 20s at surface — above 8,000 ft this will accumulate quickly once it starts.

The stream gauge data in the raw feed is from Central California and is not applicable to this objective — disregard it. No active fires. Plan your alpine start for midnight to 1 AM Tuesday night, targeting a summit by 8-10 AM Wednesday at the latest, and be back at Camp Muir before noon Wednesday. That gets you below the deteriorating weather before it locks in. If you're still on the upper mountain at 2 PM Wednesday, turn around regardless of summit proximity.