Weather update 21st January 2021

[UPDATE 25th January: A further 9.0 inches of snow fell in Idyllwild overnight, with two more inches accumulating this morning. The air temperature has not exceeded 26°F in Idyllwild today. All trails above 4000ft are heavily obscured by snow. The next detailed high country update will be tomorrow evening, 26th January.]

[UPDATE 24th January: This morning we measured storm totals of 5.75 inches of snow in Idyllwild and 7.0 inches at Devil’s Slide trailhead in Humber Park, the result of steady snowfall yesterday afternoon and evening. Snow levels were down close to 4000ft in Garner Valley and 4500ft on Skyline Trail (thanks to Florian Boyd for the latter observation). Long Valley (8600ft) added about four inches for a total of six. A further 10 inches is possible tonight and tomorrow everywhere above about 4000ft, with dusting as low as 3000ft.]

[UPDATE 23rd January: Idyllwild awoke to 0.5 inch of fresh snow overnight. All three of us had a lovely hike from home up South Ridge Trail, finding about 1.0 inch fresh snow above 6500ft, and 1.5 inches at Tahquitz Peak. Strong overnight winds meant drifts a few inches deep in patches in the trail. The high country was visibly above the cloud all morning. It lightly snowed on us during the descent, but in Idyllwild it is barely cold enough to accumulate. Another 3-4 inches are forecast to accumulate by dusk tonight at all elevations.]

Exceptionally strong Santa Ana winds on 19th-20th January were accompanied by a very minor snowfall. Our rapid ascent of San Jacinto Peak this morning involved minimal postholing, as snow was only an inch deep to about 8500ft, and with little more than two inches of fresh powder in trails up to the highest peaks. As another bonus, it was remarkably mild and windless at the Peak.

With such strong accompanying winds, the snow was plastered to all surfaces, likely giving the impression from afar of much greater snowfall. By late morning today very rapid melting was underway, with the trails more slush than snow, much of the vegetation at all elevations clearing, and the light dusting down to 7000ft had already retreated to nearer 8000ft by noon.

I recorded a video discussion at the Peak, partly describing current conditions and the storm of the previous day, but mainly regarding the genuinely wintry weather coming over the next week or so.

For an approximation of trail conditions for tomorrow, see the previous report. Snow depths reported therein remain relevant, with the addition of an inch or so from the most recent storm. Starting Saturday 23rd, fresh snowfall will change conditions significantly. Also see that prior report for details of the various coronavirus restrictions and closures.

Spikes are recommended for some sections of all trails above about 8000ft, especially in the early morning and/or for descending. Spikes may be useful locally at lower elevations also. Snowshoes will become useful possibly as early as Saturday, but certainly during and after next week.

With very unsettled weather forecast for the remainder of January, hikers should be prepared for temperatures well below freezing in the high country, and potentially dangerously low (below 0°F) when considering wind chill effects.

WEATHER For the remainder of January we should finally get something resembling a proper winter. Three successive storm systems will each bring more snow than the previous one, and by the end of the month the mid elevations (Idyllwild-Pine Cove) could have about two feet of snow, with as much as three feet around the highest peaks. All three storms are more conventional westerly storms, unlike the light snowfall mentioned above that came from the north-east.

The first storm will be on Saturday 23rd, with roughly four inches of snow expected at all elevations above about 5000ft. The second storm is close behind, arriving the night of Sunday 24th and continuing into Monday 25th. This is a much colder system – the coldest system of this winter so far – with potentially 6-10 inches of snow in the high country, and seven inches around Idyllwild-Pine Cove, but with snow falling possibly as low as 3000ft. The third, warmer storm, hits mainly on Thursday 28th. Forecast models are currently less certain about this storm, but it may bring heavy, wet snow, perhaps 10-15 inches in the high country, and several inches at 6000ft, but with a more typical snow level at or above 5000ft, with significant rainfall lower down.

At San Jacinto Peak (10,810ft/3295m) on Thursday 21st January 2021 at 0910 the air temperature was 30.6°F (-1°C), with a windchill temperature of 23.6°F (-5°C), 60% relative humidity, and a very light NE wind sustained at 2 mph gusting to 5.1 mph.

Tahquitz Peak (with Tahquitz Rock to the right) at sunrise, 21st January 2021, as seen from about Mile 181 of the PCT.
Looking south across the San Jacinto high country from San Jacinto Peak, 21st January 2021.

San Jacinto Trail Report: available for everyone, funded by readers. While all labor and time is volunteered, this Report completely depends on small private donations to cover its costs. In an especially challenging year, and with a busy winter already well underway, every contribution is invaluable. If you have found this Report useful, please consider visiting the Donate page. Thank you.

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