Powder Chaser

"That made me mad," he says. So he started using his meteorology knowledge and studying microclimates around the state to predict when and where snow would hit.

"It's a scratch-your-own-itch kind of deal," he says of the research that became an email to friends, and then a blog—"because that seemed like the right thing to do to reach more people"—and finally the powder-day predictor website OpenSnow.com.

The site is now a go-to for skiing addicts all over the country, providing detailed narratives of the weather to come, at-a-glance forecasts that predict how many inches are likely to hit your local ski area and customized powder day alerts, as well as links to webcams and videos in case you need to torture yourself staring at all the fun you're not having while fulfilling obligations at your desk job.

This year, having lost his local forecaster to a job predicting weather for the Air Force, he's taking the reins for New Mexico's predictions and studying up as storms hit Taos, Red River, Angel Fire and Ski Santa Fe with varying doses.

"Each mountain kind of has its own little forecasting tricks," he says. "There's no book that's written about that. You've just got to forecast, observe, understand if you were right or wrong and why, then try again and again. … It's just constantly looking at storm after storm and trying to figure out what differences exist due to a pattern that you can count on."

As in, did one mountain get 11 inches and another mountain 7 inches for reasons of geography that can be used to forecast what the next storm will bring? Wind direction and other mountain ranges in the area, elevation and aspect all affect how much snow falls and its density. As high elevation ski areas, Ski Santa Fe and Taos, which peak out around 12,000 feet, score lighter snow. Ski Santa Fe, so far, seems to do well with wind from just about any direction, but he's still studying how the Jemez might affect the snowfall here.

"It's fun for me to forecast a new area, because it feels like when I started in Colorado, right the cusp of trying to figure things out," Gratz says.

He pulls data from the European Center for Medium-Range Weather Forecasts and the National Weather Service, merging it and, unlike your average ski area, rounding down.

"We don't like to get people excited to then dash their hopes, so I hate to show a forecast for 8 to 10 inches, then drop it down to 2 to 4 inches," he says "We try to average things … to smooth out some of those peaks and valleys, to give a reasonable, if conservative, model."

Part of the trick is extrapolating, based on temperature and wind, just how much snowfall the precipitation predicted will produce. Computer models forecast the amount of liquid precipitation, and 1 inch of liquid can produce somewhere between 6 and 15 inches of snow. One of the difficulties in snow forecasting is sorting out which end of that spectrum we'll see.

"There are two sources of error there: The model can just be wrong about how much precipitation will fall, but then we can be wrong, too, trying to calculate what the snow-to-liquid ratio is," he says.

That ratio often depends on temperature at the start of the storm, though wind and temperature changes during the storm can affect it as well.

"If cool air comes in and that ratio changes, then all the sudden you're off by 50 percent," he says.

Warmer weather often leads to slushier, thicker snow, while those brisk days are more likely to lead to a 15-to-1 ratio.

With the temptation of Wolf Creek a beacon this year, as we have not-so-patiently waited for storms to reach New Mexico, we had to ask: What is it about Wolf Creek that compels so many of us to drive three hours north for some powder turns?

A direct line from the Pacific Ocean often sets up to deliver moisture there without having to cross any mountain ranges. Storms headed for New Mexico sometimes pass over mountains in Mexico, shedding some moisture there.

Perhaps the best news is what was on his website this week: The five-day forecast calls for more inches on the way this weekend.

Santa Fe Reporter