High Sierra Topix

Wife and I got our permit to overnight at Ediza Lake using the Shadow Creek trail on Aug 23rd and might have to change dates to September 1st instead.

Would anyone know the general weather conditions for early September at Ediza lake?

This will be our first big backpacking trip so we are trying to avoid the snow if possible.

If we were able to keep the Aug 23rd date, would the weather be a tad bit better to visit Ediza at this time of year?

Thanks!

Snow can hit any time of the year!

Later part of Sept, and especially October are the more dicier times of the year.

Beginning of Sept will be fine, a week either way is not going to make difference, just
check the weather forecasts for the area just before your departure, and either
way, just be prepared.

A week is not enough to make a difference when talking weather averages. Short term forecasts are important to check at all times of year and are pretty accurate given modern technology and science. Start checking a week out and every day after that before your trip. Snow, especially major snow, is unlikely, but it is possible all times of year. August and early September are usually the driest times in that area, with the warmest temperatures aside from July. Normally, days could range 50s to 70s with 60s likely and nights 30s to 40s with freezing possible, but not a guarantee. Check these links and read up on the weather section of HST if you want to know more. Especially if you go more remote and off summer season, learning to read the sky/weather is always advisable.

http://mammothweather.com/howards-forecast/" onclick="window.open(this.href);return false;

http://forecast.weather.gov/MapClick.ph ... 9_317nn_qA" onclick="window.open(this.href);return false;

Edit: agree with Maverick

Thanks guys and thank you for the links.

Need to go shopping for a lightweight warmer clothes just to be on the safe side.

Although I've been snowed on every month of the year at highest elevations of the southern Sierra, I don't believe it has ever snowed in modern times in the southern Sierra to the point of accumulation as low as Lake Ediza's elevation of 9263 feet in July or August. Massive cold hail storms yeah but not snow. And overnight especially on clear nights, temperatures can occasionally dip below freezing. Now above 11k it most definitely has snowed. And early June and late September it does almost every year. A few decades ago a San Jose man died mid summer trying to cross the Sierra crest after remnants of a Pacific hurricane down off the west coast of Mexico moved up over the Sierra and dumped 30 inches of snow at 11k plus pass levels.

When I was there in the third week of July it had just finished 3 days of heavy afternoon thunderstorms that came up in the early afternoons. The lows were in the low 40s and the highs in the upper 60s. A more typical temperature spread would be a tad bit warmer than that, say 45-75 unless a cool front moves in.

During a thunderstorm, though, temperatures can drop rapidly and as has been mentioned you can find yourself ankle deep in icy hail, so you have to be prepared for the wet and the cold if that should happen. Keeping your down dry is critical.

Watch the weather forecasts for the central valley. Whenever the central valley gets very hot, moisture evaporates and condenses over the Sierra in afternoon thunderstorms. These storms build during the day and you can usually see them coming. Since they do not represent a front you can almost always dry off after and proceed with plans. If the central valley stays reasonable you are more likely to have completely clear weather.

The most common disruption to the typical pattern is called a "Monsoonal flow" which simply means moisture is being pumped up the eastern side of the Sierra from the Gulf of Mexico. It is somewhat infrequent, but happened during the second week of July and resulted in heavy afternoon rains for several days. This is harder to outlast since it represents a multi-day pattern. Again, you can watch the weather for a few days before departing to get an idea of whether that is in the cards.

I found my 20 degree sleeping bag to be plenty warm enough at Ediza in July--maybe even a bit too warm. I did take and used gloves, fleecewear hat, down jacket, and rain shell.