The primary factors affecting late season (mid-March onwards) ski conditions are:
Within a group of ski areas, the one with the highest altitude and greatest proportion of steep north-facing terrain will nearly always have the best spring surface conditions. However, there are some secondary factors which also influence late season ski conditions.
Analysis By Region:
The Pacific Northwest's best March/April skiing is found at the higher altitudes of Mt. Bachelor (9,000 ft.) and Whistler/Blackcombís alpine region (over 7,000 ft. and farther north). While most other areas in the region will have deep snow bases, the surface conditions at low elevation will be slushy if it hasn't snowed recently. In May/June Mt. Bachelor still offers 3,000 total vertical of Summit corn plus lower mountain salted and groomed runs. Summer skiing, on groomed and salted permanent snowfields, is available at Timberline (1,500 vertical) and Blackcomb (800 vertical).
In California, Mammoth (top 11,000 ft.) is the standout area, running through Memorial Day in 90% of seasons and to July 4th about 1/3 of the time. Mammoth is also the only area outside the Northwest to salt its groomed runs. At Tahoe, Kirkwood's steep runs up to 9,800 ft. are the best bet until it closes in early May. Then Alpine Meadows (top 8,700 ft.) will operate into late May or June depending upon snowpack.
In Northern and Central Colorado, all of the Summit County areas operate to early May due to altitude (top 12,000 ft.) and proximity to Denver. A-Basin is the best ski area in North America by criteria 1,2 and 4 above, and thus operates through May in low snow years and well into July in good years. Copper Mt. (also predominantly north exposed) is next best in this region, followed by Winter Park. Vail and Breckenridge are more erratic due to substantial amounts of terrain with sunny exposures. Steamboat, despite its high snowfall, has the lowest altitude and worst exposure in the region.
Nearly all of the Southern and Western Colorado areas are ideally suited for late season skiing for both altitude (up to 12,000 ft.) and north exposures. Aspen/Snowmass, Crested Butte, Telluride plus Taos in New Mexico all have steep terrain which can retain a packed powder surface well into April. Due to remote location, these areas often close in mid-April with their deepest snow depths of the season.
In Utah, the best late season spot is Snowbird from both altitude (top 11,000 ft.) and terrain perspectives. It is also the only area open in May. Alta and Brighton top out 500 feet lower than Snowbird and have more variable exposures. Solitude and Park Cityís Jupiter Bowl extend up to 10,000 ft. Utah is the warmest of the continental ski regions of North America, so spring conditions are common below 9,000 ft. from mid-March onwards.
Few of the Northern Rockies areas have good exposures, and spring surface conditions on ungroomed terrain like much of Jackson Hole can be very difficult. In the U.S. Big Sky has the highest altitude (top 11,000 ft.) and coolest temperatures. Most of the Kootenay areas near the U. S. / Canada border are relatively low in altitude (nothing over 7,000 ft.) and spring conditions are likely. The Okanagan areas are farther north and a bit higher and cooler than the Kootenays. The Alberta Rockies, despite low snowfall, are the best bet for late season for both higher altitude and coolest temperatures. Sunshine (9,000 ft.) and Lake Louise (8,500) are also the only areas in the region open later than mid-April, although late season coverage can be an issue in below average snow years.
Late season snow conditions in the Northeast are usually difficult. Good spring surface conditions are dependent upon consistent freezing of the snowpack most nights and low humidity. The East usually fails on both counts due to low altitude (nothing lift serviced over 4,200 ft.) and with increasing rain frequency in the spring months the surface often resembles a granular snow cone. It would be quite rare for eastern conditions in April and May to be comparable to the western areas we have recommended. It is not surprising that in spring many eastern skiers climb Tuckerman's Ravine for its steep runs starting above 5,500 ft.