Mt. Shasta – Avalanche Gulch

The trip window splits cleanly into two phases: Tuesday is a weather day, Wednesday is your summit day. Tuesday's forecast shows 81% precip probability with light snow at base elevation (34°F), which means accumulating snow above treeline — Avalanche Gulch starts climbing above 8,000 ft and the summit is at 14,179 ft. With an overnight low of 30°F at the valley floor and a standard lapse rate (~3.5°F per 1,000 ft), expect temps in the single digits near the summit during Tuesday night. Tuesday's 18 mph SSE surface winds will likely double at ridgeline elevation — call it 35 mph gusts on the upper mountain, which combined with new snowfall means wind-loading on lee aspects. The Mount Shasta Avalanche Center has no formal rating issued (early season, snowpack is essentially non-existent right now with 0 inches at Annie Springs at 6,021 ft and 0 inches at McNeil Canyon), but the bulletin guidance is right: any new Tuesday snow on a bare or minimally consolidated base is worth watching. Probe for hollow sounds and watch for cracking on steeper sections of the Gulch on your approach.

Wednesday is the window. Mostly sunny, winds 3–7 mph north at the surface (call it 10–15 mph at elevation — very manageable), and temps recovering to 40°F at base. That's a legitimate summit push day. Plan your high camp at Helen Lake (~10,400 ft) Tuesday evening before the brunt of the snow, rest up, and launch for the summit no later than midnight Tuesday to Wednesday to top out before any afternoon convection. Wednesday night brings 7–13 mph NNW winds and partly cloudy skies — fine for descent. Thursday looks even better: sunny, light north winds, 42°F.

The stream crossing data shown is from gauges well outside the Shasta drainage and isn't relevant to your approach. The Avalanche Gulch route this early in November is primarily a scramble on volcanic rock with whatever new Tuesday snow sits on top — crampons and ice axe are warranted given the overnight refreeze, and the icy upper headwall could be genuinely technical with a thin snow layer over hard basalt. Microspikes may not cut it above Red Banks; bring your full mountaineering kit.

Daylight is your other constraint: 10h 19m with a 5:03 PM sunset means a midnight start gives you roughly 17 hours to summit and return to camp, which is comfortable. But if Tuesday's snow is deeper than expected, pace accordingly. Don't push past noon on the summit ridge regardless of how good it feels — descend before thermal softening turns any new snow unstable.