Mastering the art of corn

Anyone who has skied in Tahoe between the months of March and May has experienced corn snow. Swooshing along under bright warm sun in a T-shirt and sunglasses, the snow doesn't stick to your skis like slush as you glide over it without effort almost like powder.

Basically, corn snow is caused by a cycle of freezing and thawing that allows the moisture to percolate down through the snow, leaving "kernels" of ice on the surface that haven't yet bonded together to form one solid mass of slushy cementŠlike snow. Because of that delicate cycle of snow melt, corn snow can only be found at certain times on certain aspects during a sunny spring day.

Go out too early and it's not ready, get there too late and it's all gone.

"It's like a snowcone; all the good flavor is at the bottom," said Chris Fellows, director of Truckee's North American Ski Training Center (NASTC). "If the snow cone goes down three feet, you missed it,"

Fellows said the variables that go into corn snow make it very hard to predict and very hard to master. The aspect of the sun, where it is in the sky, the pitch of the slope, what conditions were like in previous days and how deep the snow is are all factors in corn quality.

"There's so many variables," Fellows said. "One aspect can be turning and another can be frozen."

Because the corn follows a melt-freeze cycle, skiers and riders can follow the sun around a mountain and keep up with the corn. Within that melt-freeze cycle, the nighttime low that causes the freeze is possibly the most important ingredient for good corn snow.

Said Prosser resident and longtime local backcountry enthusiast Bill Sinoff, good corn is caused by icothermal snow - meaning the snowpack remains the same temperature throughout its entire depth. If the snowpack remains icothermal and the nighttime low is cold enough to freeze the entire snowpack, the corn will remain longer than if only the top layer froze, leaving just a small window in the melt process before riders are slopping through bottomless wet cement.

Sinoff said that on a nice day it doesn't take a slope much time in the sun for the skiing to get good. On such a day, a slope can be "ripe" after 15 minutes in the sun.

Because of that, early summit times are key to getting the most out of a day. Start with an east-facing slope as the sun rises, then work around to the south and finish with the west face, which should turn latest under the afternoon sun.

Fellows, who has skied all over the world with NASTC, says that the climate in the Sierra lends itself to corn snow better than almost anywhere.

Deep snowbases that are allowed to sit in constant sunshine melting and freezing, make the corn here more abundant than nearly any other place on the planet.

Regions like the Pacific Northwest get an incredible amount of snow, but the constant cloud cover doesn't create that rapid melt-freeze cycle. And in areas such as Colorado, it is sunny but rarely warm enough for the melting necessary before velvety corn forms.

Fellows said it takes experience and the knowledge to know when, where and how long corn will be found.