High Sierra Topix

Hiked Tuolumne Meadows -> Cathedral Lakes -> Echo Lake -> Matthes Lake -> Nelson Lake -> Tuolumne Pass -> back to Tuolumne Meadows. Elevations 8,600 to 10,500 feet. Mostly calm or light breezes. Basically zero mosquitoes. I think I saw 3 on the entire trip.
-Phil

I camped at Cora Lakes in Sierra National Forest 8/9-15, and hiked to surrounding areas, including Sadler Lake, and over to Bugg Meadow. Elevation 7200-9200 feet. Skeeters were mostly relegated to wet spots (drying streams, springs) in woods while hiking. At lakes, it was an occasional mosquito. I would apply picardin for hikes, just to deal with those wet areas. Overall, mostly 0 or 1, some 2s while hiking.

Hiked Emigrant Wilderness from Gianelli Trailhead past Chewing Gum to Toejam to Piute and back to Gianelli on a 3 day 2 night trip (8/14-8/16) and never pulled out the feet. Had three or four bites I didn't notice when I got back - but I'd probably have that few as well from walking outside at home this time of year.

Spent two nights at second lake, no mosquitos whatsoever. We spend the third night at fifth lake and saw only a few at dusk. I got maybe 2 or 3 bites the whole trip.

Kennedy Meadows to Emigrant Lake and back. Four days at Emigrant Lake / 6 people and not one bite or even a mosquito seen by anyone.

Although it may seem there are no mosquitoes left, that is never true in some marshy areas. I didn't apply repellent this summer on either of my 2 backpacking trips however there were a few that rose out of marshy areas in certain conditions. On each trip I spent time near some large marshy areas that in prime mosquito season are especially notorious. Consider this image in the Rock Creek basin I shot on August 6 where I camped one night and spent time mid day sun laying exposed out on a rock after enjoying a refreshing dip in the stream. No sign of squeets all day even though there were only minor breezes and temperatures were balmy.

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This is not a meadow but rather a large marshy willow grassland that until mid summer is usually covered by shallow water below the grasses. In June it is a large shallow grassy lake. There are of course numbers of such places in the Sierra like below Blaney Meadows, at Little Bear Lake, or above Mildred Lake and given the shading, wind cover, and predator protection down inside grasses are ideal for breeding all manner of aquatic insects including mosquitoes. After damselflies and dragonflies hatch, the majority of mosquitoes in such areas are rapidly eaten until the only ones remaining are those that have evolved to only rise out of hiding at limited periods of day and weather conditions.

Both damselflies and dragonflies do not tend to be active early morning or late afternoon preferring to remain still on vegetation where they overnight. That is why minor numbers of whiny blood suckers did appear about 6pm when their predators retired that day after breezes became especially light.

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Another similar situation from July 25 in the above larger similar environment of wet willow grasslands above Mildred Lake. Even at 9am with hardly a breeze there were no mosquitoes about and then a moderate breeze arose. However about noon on a warm day when cumulus build ups covered the sky, breezes waned again to dead calm. I went to work on a particularly aesthetic seep spring and upon leaving, suddenly significant numbers of mosquitoes had risen up and were hounding my retreat. Because of the way the females whine, when some begin to do so in such ideal weather conditions because they notice prey like a visiting deer or in this case this skinny human, others hiding down in the grasses will hear such and by instinct then rise up to attack. So even though it may be late season, one will be wise not to totally be unprepared if visiting such areas.