Planning a ski vacation well in advance is a tricky proposition. Early birds can’t possibly know what snow conditions will be several months or weeks out. And those who wait for flakes to fall risk missing out on special deals — if there is any availability left at all late in the booking game.

One strategy for early bookers is to consider where the snow has fallen most in the past. The highest snowfall averages over the course of more than 10 years include at Jay Peak in New England, Alta and Snowbird in Utah, and Revelstoke in British Columbia, according to Joel Gratz, the founder of Opensnow.com, which offers snow reports and forecasts by a group of powder-hungry meteorologists. “However, every season is different,” he points out. “And most often, snow forecasts for an entire season are not reliable, so we can’t necessarily use the past as a perfect guide to the future.”

Case in point. If you avoided Colorado this holiday season because of dismal early conditions last year, you sorely missed out. Plentiful snow allowed ski resorts to open early with more terrain than usual. Aspen Snowmass had already received more than 130 inches by the end of December, with more than 5,300 acres of terrain open for skiing, compared with 1,900 the previous year. Vail Mountain’s Back Bowls opened just after Thanksgiving, marking the third time in the last decade that the backside of the mountain has opened so early, and all the resort’s 5,289 skiable acres were open before the New Year. Breckenridge, which reported more than 172 inches by early January, had opened all five of its peaks by Dec. 12 — the earliest all five were open in the resort’s history.

Scientists say climate change will make the booking equation all the more complicated as temperatures continue to rise. The Climate Impact Lab, a group of climate scientists, economists and data analysts from the Rhodium Group, the University of Chicago, Rutgers University and the University of California, Berkeley, released an analysis last year projecting that if trends continue, some popular ski resorts could lose as much as a month of the season within the next two decades.

Consider the resort’s track record. While snow conditions can vary from year to year, some regions consistently receive deep powder during the course of the ski season. The southeast corner of British Columbia, which encompasses the Kootenay Rockies, is “a safe bet,” said Dan Sherman, the chief marketing officer at Ski.com, which offers a list of the region’s “reliable” deep-snow resorts. There are eight major ski resorts on “the Powder Highway,” along with small mountain towns and heli- and snowcat-ski operators.

Be patient and remain flexible. If powder is your No. 1 criteria, flexibility is key. Start paying attention to the weather about 10 days out and then plan your trip just five days in advance, locking in lodging and flights about two to three days out, recommends Mr. Gratz of Opensnow.com. “Weather forecasts are only reliable at showing trends — warm, cold, snowy, rainy — about 10 days away,” he said, adding that “the details of forecasts are not reliable until about three to five days before a storm. So if people want to chase the best conditions, they need to wait to book until much closer to that time.”

Most airlines will allow you to apply the cost of your ticket toward a future flight within one year of the purchase date, minus some hefty change fees. One exception is Southwest Airlines, which has a free change policy, and only charges the cost in fare difference when you rebook. Rental car companies and hotels will also allow you to change or cancel your reservations within a day or two of travel. This rarely applies to the best available rate however, so read the fine print carefully to avoid any penalties.

You can even purchase snow insurance. Ski.com offers a no-snow insurance policy from Dec. 15 to March 30 for 6.5 percent of the cost of your trip. During that time, if 50 percent or more of the resort is closed, travelers get their money back.

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