As far as Joel Gratz is concerned, there’s one good thing about the reservation system that Vail Resorts implemented this pandemic ski season to limit the number of guests mixing on its mountains: it should change the slothful ways of his nemesis, the lazy powder skier.

“What I’ve heard is that most days, people will be able to get a reservation,” says Gratz, the founding meteorologist and CEO of OpenSnow.com, a powder-forecasting app that predicts snowfall at more than 2,000 peaks worldwide. “But just the threat of a supply constraint will get more people planning.”

Gone (for now) are the days when the procrastinating powder hound could wake at dawn on the Front Range or downvalley, check the snow stakes and mountain webcams at Vail and Beaver Creek, and crawl in traffic up Floyd Hill or around the Dowd curves with the hopes of making it onto the mountain in time to add fresh tracks to the Back Bowls or Royal Elk Glade. Because now, a week before they can enter the White Room, powder skiers must enter the Waiting Room, the queue at epicpass.com where a limited number of “week-of” reservations—available slots for the following week—are released every Wednesday.

Gratz’s chief advice is pretty straightforward: a week out, if it’s uncertain whether a storm will be tracking through the valley on a Wednesday or a Thursday, hedge your bet and book both days. And to help maximize your chances of getting the goods, this season Gratz has added some serious upgrades to his app. In addition to long-range forecasts, OpenSnow (opensnow.com; annual subscriptions from $29.99) now offers a Harry Potter–esque Marauders Map for powder hounds—radar-enabled overlays of each resort, showing the amount of snow on the ground and where snow is falling on particular runs.

“We all want to ski and have great powder,” says Gratz, a Boulder resident who has degrees in meteorology and business. “Hopefully we’ll make people appreciate the science that has advanced forecasting and what we are able to do.”

To offset the capriciousness of Ullr, Gratz relies on a team of 14 forecasters who are experts in the nuances of the microclimates of their particular zones. Gratz’s own territory includes Vail and Beaver Creek, his home-away-from-home mountains, where he has logged hundreds of powder days over the past 15 seasons. His trade secret for Vail and Beaver Creek? When a storm is coming, pick which resort you will ski based on the winds: a northwest wind can double the amount of snow that falls at Vail versus Beaver Creek, while a west wind can up the ante at Beaver Creek by 30 percent. But even this Nostradamus of the gnar draws a line at divulging his secret stashes.

“I don’t want to give away the farm,” is all he’ll allow, adding, “The fun of skiing is that moment of discovery, when you happen upon that line in the trees, and you’re overjoyed.”

In other words, Gratz is happy to help you plan for exactly when the magic may happen, but it’s up to you to divine precisely where.