Knowing snow line is key to planning winter Tahoe trip

Each time a storm swings through the Bay Area and sails toward Tahoe, we all wonder the same things: How much snow will the High Sierra get? When will it arrive? Where will it hit?

The key to unlocking in recent years — the mystery to all of these mostly going up due to is understanding the climate change, says Michael snow line. It’s an elevation Pechner of Golden where snow will typically West Meteorology. stick to the mountains at “In the Sierra, it often any given time. In places rains where it used to like Tahoe, the seasonal snow,” Pechner says. snow line has been changing “Over time, total annual snowfall is shrinking.”

Some quick, back-ofthe-napkin calculus can help you plan a successful weekend trip in the mountains.

You can calculate the snow line in the High Sierra by using the formula for temperature lapse rate: The temperature drops 3.5 degrees for every 1,000-foot gain in elevation, a rule of thumb. In the mountains, you tend to get snow with a surface temperature of 34 degrees. Thus if you know the temperature in Sacramento while raining, you can calculate the snow level for your route and destination in the mountains.

Let’s say you’re driving to Tahoe and you hit rain with a temperature of 58 degrees in Sacramento (30 feet above sea level). How would that translate in the Sierra? Because the typical snowfall temperature is 34 degrees, to get snow, the temperature in the mountains would need to be 24 degrees colder than in Sacramento. Using the temperature lapse rate, 24 (degrees colder) divided by 3.5 (temperature lapse rate) equals 6.9 (added to your elevation). Hence, you would likely get snow at about 6,900 feet. That would mean you’d see snowfall and likely hit chain conditions and low visibility at pass levels; you’d get snow at the higher elevation of ski areas; and you should expect rain at lake level around Tahoe.

This is just one example; each storm is different.

To help you get the most out of your weekend in Tahoe this winter, here’s a synopsis of what types of activities open up and where, by elevation, when it snows:

Tom Stienstra is The Chronicle’s outdoor writer. Contact at tstienstra@ sfchronicle.com, Facebook or Twitter: @StienstraTom

Tom Stienstra / The Chronicle The view of 9,103-foot Castle Peak from Castle Pass, located across Interstate 80 from Boreal Ski Area near Donner Summit. In low snow conditions, you can climb Castle Peak in winter with Yaktrax and ski poles.