Snow storm 4th December 2019

Our third storm of this winter passed through on Tuesday night and today. It started gently snowing at San Jacinto Peak at 1830 last night. This system was much milder than the previous two this winter. Consequently much of the night the precipitation fell as freezing rain even at 10,800′, with only about 2-3″ of snow accumulating overnight. It subsequently snowed steadily from 0700 to 1330 today, with total new accumulation of about 8″ (replacing the same amount lost at the Peak to melting in preceding days).

A short video from 1400 this afternoon at San Jacinto Peak is available on YouTube.

The lowest elevation reached by the snow level was about 8400′. Saddle Junction (8100′) lost at least 5″ of snow to rainfall in a day, while Annie’s Junction (9070′) gained about 4″ of fresh snow, but lost about 6″ to rain and melting.

At times sleet was falling and often failing to accumulate in Long Valley (8600′) in the morning, which reported 1.0″ of rainfall, before a couple of inches of snow accumulated there in the early afternoon.

On my descent this afternoon I ran into a misty, windblown, drizzle at 9900′, which stayed with me all the way down to Idyllwild.

In Idyllwild (at 5550′) an impressive 1.96″ of rain fell between Tuesday and Wednesday nights.

Note that the USFS gate at Humber Park is now closed. There are nine legal parking spaces – available for all uses – just below the gate (near the upper Ernie Maxwell trailhead). The next closest legal parking is 0.1 mile downhill on Forest Drive.

Currently many major trails have not been traveled and are obscured by fresh snowfall above 8500′. Good snowshoe tracks exist for Humber Park to San Jacinto Peak and from the Tram to Wellman Divide. Cautious navigation is recommended everywhere.

Snow depths measured today are listed at the foot of this posting. Melting of the major Thanksgiving snowstorm had been significant in many areas, with 20-30% of last week’s snowfall lost above 7000′, and much more lost below that elevation.

Snow depths are currently good for snowshoeing almost everywhere above about 8000′ elevation. This will change with rapid melting anticipated over the next ten days.

Microspikes will become increasingly useful at all elevations over the next few days as established trails become consolidated by hiker traffic and undergo freeze-thaw cycles (emphasis on the thaw). They are especially useful for descending trails when they become icy and compacted.

Waterproof footwear is strongly recommended on approach trails at least (e.g. Devil’s Slide, lower Deer Springs) due to extensive slush and water runoff in the trails.

Despite relatively mild weather between storm systems, hikers should be prepared for temperatures at or below freezing in the high country, and potentially well below freezing when considering windchill effects.

WEATHER The warming rollercoaster ride that defines the weather in the San Jacinto mountains nowadays will continue into December. Warm conditions immediately following this latest storm will take high country temperatures above freezing tomorrow. A brief cooler storm system at the weekend (7th-8th December) will produce moderate rain at mid-elevations (to 9000′) but very little snow is forecast higher up. Then it dramatically warms yet again to temperatures well above seasonal in the week 9th-13th December, with 40+°F likely at the highest peaks and rapid snowmelt likely everywhere.

At San Jacinto Peak (10,810ft/3295m) today, Wednesday 4th December 2019 at 1350 the air temperature was 25.4°F (-4°C), with a windchill temperature of 9.0°F (-13°C), 100% relative humidity, and a sharp WSW wind sustained at 9 mph gusting to 21.4 mph.

At the Peak on Tuesday 3rd December 2019 at 1645 the air temperature was 32.6°F (0°C), with a windchill temperature of 18.4°F (-8°C), 56% relative humidity, and a brisk SW wind sustained at 13 mph gusting to 20.7 mph, while heavily overcast.


All trails above about 8000′ are snow-covered, with depth depending on elevation (see below).

Reliable, well-traveled tracks were currently in place only for Devil’s Slide Trail, from Saddle Junction to San Jacinto Peak, and from the Tram through to Wellman Divide.

Devil’s Slide Trail this evening was only about 50% snow-covered from the trailhead to 7500′, and had significant water erosion due to runoff. A similar situation is likely at least on Deer Springs Trail below Strawberry Junction.

SNOW DEPTHS measured today are as follows. Average depth is given. Drifts will be much deeper than the average in places. Altitudes are approximate.

San Jacinto Peak (10810′): 36″ (had melted to 28″ by 3rd December)

Wellman Divide (9700′): 16″ (had melted to 12″ by 3rd December)

Annie’s Junction (9070′): 18″ (had melted to 20″ by 3rd December)

Saddle Junction (8070′): 13″ (had melted to 18″ by 3rd December)

Devil’s Slide Trail at Humber Park (6550′): 1″ (had melted to 5″ by 3rd December)

Idyllwild (at 5550′): 1″ (remaining from Thanksgiving storm, not new accumulation.

Wellman Divide (9700′) this afternoon Wednesday 4th December 2019 (above), and the same view 24 hours earlier on Tuesday 3rd December 2019 (below).

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