Mosquito Prediction

Questions and reports related to Sierra Nevada current and forecast conditions, as well as general precautions and safety information. Trail conditions, fire/smoke reports, mosquito reports, weather and snow conditions, stream crossing information, and more.
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watsonic
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Mosquito Prediction

Post by watsonic »

Hi all,

Just submitted a report on the Mosquito Reports thread.

Wanted to dig a bit further and ask for some general guidelines and reading material for predicting the bugs better. I know these reports are the best thing, but if I want to extrapolate from say a report 2 weeks ago for a general area I'm interested in how do this? What if the lake I want to camp at is nearby but has different qualities (e.g. elevation, nearby drainage, forest...) ?

I have specific questions like:
  • In the summer, typically how fast (at a weekly rate) do mosquito max elevation levels climb?
  • How does temperature play in?
  • Once a place reaches level 3-4, how long does it take for it to drop off to 1-2 or below? Are there some places that never really do? How to know?
  • Forested / shady areas and swampy areas tend to have more mosquitos. What are other factors?
Any pointers appreciated!
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rlown
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Re: Mosquito Prediction

Post by rlown »

Peak skeeters follow 2-5 weeks after the snow melts, and the flowers bloom. It follows the melt, depending on weather. Then it lasts for maybe 3 weeks to a month. We're on a late pattern this year. Every place is different depending on micro climate and wind pattern.

Bring the DEET and the head net this year.
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giantbrookie
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Re: Mosquito Prediction

Post by giantbrookie »

I figure there are two big factors to consider in the severity of mosquitoes. The first would be as Russ noted, which is the connected to the presence of wet soggy areas following the snowmelt and also tied to the warmer temperatures associated with summer. For example, Emigrant Wilderness, which has lots of bodies of stagnant water, and swampy areas, has a well earned reputation has having lots of summer days and nights in which mosquito conditions are very severe. As noted above, the time-of-year matters because in early season, just after the thaw, there is a ton of water around but (1) it is still pretty cold at night and (2) there hasn't been that much time for the mosquitoes to breed in the newly created bodies of water. In the late season, the nights get cold and this is what tends to end the "mosquito season" because there is usually still plenty of standing water present in many High Sierra wilderness areas.

Superimposed on this, though, is the weather of the moment. A good and consistent breeze tends to really keep the bugs down. Many areas in which you'd be eaten alive are benign when the wind blows. I can remember dreading a midsummer walk through Big Wet meadow in Cloud Canyon, but receiving the gift of a stiff breeze when I walked through--it totally kept the bugs away. In my experience warm and calm evenings anywhere in the Sierra during the summer are bad news, even in rather dry areas. Some of the worst examples I recall were (1) a particular weekend in 1975 when I climbed Olancha Peak. The area where we camped was totally dry. Yes there was a meadow in the vicinity but we were not right on the fringe of it. The day and night was warm and calm and so many mosquitoes landed on us at one time that our clothing looked like it was covered with black fur (and we were using DEET, too). (2) a week in early July 1996 in the area from New Army Pass to Shepherd Pass. Again, there were warm days and nights and relatively little wind. The "black fur" covered us over more of the day than the Olancha trip including areas very far from water, such as the section of the PCT btw Whitney Creek and Wallace Creek. So warm were the temps that the mosquitoes didn't go away night, and they attacked in large numbers even at the top of New Army Pass (12300' elevation) and I set a personal High Sierra altitude record for highest biting mosquito being bitten at 13500' when climbing Mt Barnard.

It was conditions such as those above that established my habit of choosing campsites on comparatively high ground and in exposed areas, usually much further from water than the minimum required distance. In such areas I tend to get a better breeze which cuts down on the mosquitoes.

Anyhow to get back to your question, in addition to the type of ground traversed (lots of soggy areas?), I also examine the local and up-to-date weather report to assess mosquito harassment potential. These predictive factors can be wrong, though. Last week I was in Desolation Wilderness and the daytime temps hit the mid 80s and the lows didn't drop below about 60 on the first night. In addition, little wind was predicted. There was lots of standing water and soggy places, so I feared the worst. Yet the mosquitoes were mild on average and only rarely got to moderate levels. A reasonably consistent breeze certainly helped but it certainly couldn't be the only reason the mosquitoes were so mild in conditions that otherwise predicted disaster.

The bottom line is that mosquito severity can be partly predicted by location, time-of-year, and local on-spot weather conditions, but there are times these predictors don't work well, either.
Since my fishing (etc.) website is still down, you can be distracted by geology stuff at: http://www.fresnostate.edu/csm/ees/facu ... ayshi.html" onclick="window.open(this.href);return false;
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Re: Mosquito Prediction

Post by SSSdave »

Mosquito levels in the Sierra Nevada is a complex issue with many factors far beyond what your questions address. At best even to those of us with decades of experience, predictions are a vague guess that often don't come true. Much like trying to predict wildflower blooms at elevations and over complex landscapes with different exposures.

With mosquitoes, there may be dozens buzzing about a person if taking a mid day break sitting down in a marshy area while 100 yards away where terrain changes to bright bedrock granite, none. Yet about 7pm at that same bedrock granite area after breezes calm it can be just as bad as it was at the marshy area. And the next day after a chilly night after sunrise at the marshy area, there may be none about until about 8am when sun finally shines down onto the vegetation and trees where mosquitoes hide in a stupor during the night as temperatures drop. This last week I was about a timberline elevation where mid day mosquitoes were maybe a 2 in drier areas and 3 in lush wet forest. An epic thunderstorm hail storm over the local area dropped 4 inches of hail in about an hour. Next 3 days squeets were a 1 or weak 2 because they had all been massacred by the hail. And their wigglers in shallow pools were all dead too. A cold following night with temps a bit below freezing iced over not only melt pools and ponds but also a large lake just below 11k. Doing so also suffocated more wigglers.

Each year the board has had a dedicated mosquito thread. Search for those from the last few years where much advice has been given. When you get done reading such then check info at these links:

https://en.wikipedia.org/wiki/Mosquito
http://mosquito.ifas.ufl.edu/

David
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kpeter
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Re: Mosquito Prediction

Post by kpeter »

Yes, it is complex, but there are a few simple rules.

Drier is better than damp.
Breezier is better than still air.
Further away from water and greenery is better than closer.
Later in the season is better than earlier.

Most areas only go through one major hatching in a season, and it takes about 6 weeks for that hatching to run its course, although it is more a tapering off than an abrupt departure. The hatching cannot begin until snowmelt, and there is about a week needed for the the mosquitos to reach flying stage. Hence, most people believe that weeks 2-5 after snowmelt is the worst time for mosquitoes.
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Re: Mosquito Prediction

Post by freestone »

I go by the solstice. Seems like as the summer solstice approaches, bug activity intensifies, after the solstice, activity seems to drop off. By mid to late August there is usually a brief cold snap that really zaps them, then by September they are all gone.
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