Trail and weather update 4th September 2019

[UPDATE 6th September: spectacular thunderstorms over the whole mountain yesterday afternoon produced violent precipitation. Trail erosion caused by runoff was widespread all the way to San Jacinto Peak this morning. In Idyllwild we received 0.77″ of rain, most of it in less than 30 minutes, during which we were also bombarded by intense garbanzo bean-sized hail for at least five minutes!]

Ascents of San Jacinto Peak yesterday and Friday included full surveys of the main eastern and western high country trails. Most other trails, and the Tahquitz area meadows, were thoroughly surveyed last week.

The status of water sources, many of which were rechecked yesterday, is unchanged from the last update linked here, and news on the status of road closures is also described at the foot of that posting.

Three storms occurred in the past two days. Relatively light rainfall occurred on Sunday and Monday afternoons (0.03″ and 0.08″ respectively in Idyllwild), though with heavier rain locally in the high country. Pea-sized hail was reported in Little Round Valley on Monday afternoon.

However in between there was a spectacular overnight thunderstorm between about 0130-0300 on Monday 2nd, which produced severe localised rainfall and strong winds. In Idyllwild less than 0.2″ rain fell, but Palm Springs and the Desert Divide recorded about one inch. One cell passed over Pinyon (1.4″ rain) tracking NW over Garner Valley and Lake Hemet. The San Jacinto high country was hardest hit by a very intense storm cell, with 2.46″ of rain in under two hours at Long Valley. Evidence of substantial run-off is obvious on all the high country trails. Colleagues overnighting at Tahquitz Peak fire lookout reported winds in excess of 40mph – even blowing out one of the windows – and hundreds of lightning strikes, none of which thankfully hit the tower itself.

Hikers should always be prepared for rapidly changing weather conditions in the high country in summer (as the last few days have demonstrated!). Monsoonal conditions are always a possibility in this season (see Weather below). Thunderstorms with lightning, precipitation, and rapid temperature drops, can occur in the high country even when such storms are not forecast.

WEATHER Humid, potentially monsoonal, summer weather continues for the next couple of days, with well above-average temperatures for September. At the weekend (7th-8th September) temperatures are forecast to drop dramatically to seasonal norms, and it will start to feel autumnal in the high country.

At San Jacinto Peak (10,810’/3295m) yesterday, Tuesday 3rd September 2019 at 0815 the air temperature was 52.5°F (11°C), with a windchill temperature of 49.0°F (9°C), 68% relative humidity, and a light SE breeze at 4 mph gusting to 8.6 mph.

At the Peak on Friday 30th August 2019 at 0815, the air temperature was 54.0°F (12°C), with a windchill temperature of 49.3°F (10°C), 33% relative humidity, and a steady W wind at 9 mph gusting to 11.6 mph.

The creek in Little Round Valley continues to flow, 3rd September 2019.


All trails, including the entire Pacific Crest Trail throughout the San Jacinto mountains, have been free of snow since the end of June.

Hikers planning ascents of Skyline Trail are reminded that the Palm Springs Aerial Tramway is closed for maintenance 9th-29th September.

The Pacific Crest Trail remains open at the rockslide near Antsell Rock (Mile 172.5). The video report from late May (available here) can be useful for deciding whether to try to hike around the rockslide.

Forest Service closures to the Boulder Basin and Black Mountain Group campgrounds (both accessed from Black Mountain Road), and Dark Canyon Road, will remain in place all year. Consequently, Dark Canyon campground is also closed, and there is no vehicular access to Seven Pines trailhead.

Willow Creek Trail has had almost all obstructing trees removed this summer. As of Monday 26th August there remained two trees down on the trail between Willow Creek and Hidden Divide (one on USFS land is passable by a temporary alternate trail, and one on State Park land can be climbed over). This is a huge improvement from the nearly 30 trees down on this trail in June.

Seven Pines Trail has at least 35 trees down, almost all above 7500′ elevation. State Park has scheduled work this month to remove some or most of these obstructing trees. This trail has been very lightly traveled since 2018, and is indistinct in places. Hikers without considerable prior experience of this trail should take great care with routefinding.

The Caramba Trail from near Reeds Meadow through Laws Camp to Caramba, and the Cedar Trail from Willow Creek Trail to Laws, are not maintained. Temporary signage to this effect has been in place since the end of June. Both trails are indistinct in places, and hikers without considerable prior experience of this area should use cautious navigation.

The Cranston Fire closure order expired at the beginning of August. Although this does not impact the wilderness trail situation, it does mean that the popular dirt roads and mountain bike trails of the May Valley and Bonita Vista roads area are now open.

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