Mount Whitney may be one of the most-visited mountains in California. The permit is hard to come by to climb in the regular season, but in the winter the mountain transforms itself into a completely different place. Snow can be very beautiful, but with the beauty comes risk. Venturing to the wilderness in the winter takes completely different skill set.
Whitney Portal Road closes during the winter. Some brave soul might attempt to hike all the way from the bottom of the road, but there is a small window where the road opens while the snow is still present on the route and the permit season hasn't started yet.
In a heavy winter season, snow can cover the ground all the way to the bottom of North Fork. As a result, it is a straight shot toward Lower Boyscout Lake instead of going through Ebersbacher Ledges (E-Ledges). From Lower Boyscout Lake, the route to Upper Boyscout Lake will be pretty obvious. Here you should decide whether to camp or continue to Iceberg Lake. Upper Boyscout Lake is well protected from the wind, but it is farther from the summit. Be prepared to build a snow wall to have some protection from the wind should you continue.
The route all the way to Iceberg Lake is usually pretty mellow, but climbers should proceed with caution while traveling in snow. The slope from Iceberg Lake toward the Notch will most likely be covered in packed snow. It is about a 40- to 45-degree slope.
During this time, make sure you have all the necessary equipment—crampons and ice axes—and know how to use them to self-arrest. Based on the conditions, you might also need some rope, a rappel system, and snow and rock protection. The last 400 feet to the summit can be icy and dangerous.
Nearing the end of the spring season when snow starts to melt rapidly, conditions will change. The easy slope that covered the North Fork will start to melt, making it dangerous to cross the thin snow bridges that can collapse anytime. If you're not careful, you can fall into the rapidly moving water. The creek will be harder to cross with the high-water level. At this point you might have to use E-Ledges to reach Lower Boyscout.
It can be a wonderful experience to visit the area when the snow is present. It has some challenges, but it will be very rewarding. If a winter experience is not what you're after, consider a summer ascent of this famous peak.
Remember to always check snow and avalanche conditions before heading out.