You see Klaus Wolter's name in the paper every winter. The German native is a climatologist with CU's Cooperative Institute for Research in the Environmental Sciences and one of the top experts on El Niño.
Since El Niño is back warming up the water in the South Pacific, Wolter predicts, well, a relatively unpredictable weather pattern. He's none too optimistic that today's storm is a harbinger of things to come -- at least in the near term, anyway. After the jump, Wolter answers our most pressing snow-related questions for the 2009-10 season.
On the Edge: So what's the forecast? Is it going to be a good winter for skiers and snowboarders in Colorado?
Klaus Wolter: Despite a cool and somewhat snowy start to December, I don't hold out much hope for snow in the next two months, especially at the highest elevations where we need a 'steady diet' of storms (one or two per week) to keep building the snowpack this winter. During winter, El Niño often results in a so-called split-flow regime where storms either track to our north or to our south rather than right across Colorado. The upside is that we tend to get less windy winters during El Niño, especially east of the Continental Divide, and we tend not to get extremely cold. And we often see a turnaround towards more frequent storms in February and March during El Niño that could give us decent late season skiing. Compared to many lower elevation resorts, we still have the advantage that we don't have to worry about rain (instead of snow) in the next few months, so that even a below-average season in Colorado offers better skiing than above-average snowfall in many other places.
One more point: lower elevation skiing -- namely cross-country skiing -- is often better with El Niño situations, since we get fewer Chinooks, and El Niño does increase the chances for the bigger snowstorms from October into May. This does not mean that every El Niño winter produces such whoppers -- and we already had one in October -- but the odds are definitely increased. So, if you can lay down a good amount of snow, say, in December, that snow can stick for a pretty long time, giving us long-lasting snowcover on the eastern plains. 2006-07 was one such case (I call it the El Niño winter on steroids) where we had three big snowstorms in succession from just before Christmas until early January, so that snow took a couple of months to melt. 1982-83 and 1987-88 are other examples of such El Niño winters with long snowcover seasons due to heavy snows in December. However, most El Niño winter seasons are more like 2002-03 or 1991-92 when we had little snow on the ground in mid-winter, along with many mild days.
On the Edge: How about the near-term snow forecast for the state's mountains -- the remainder of the fall -- and the outlook for spring?
Wolter: All in all the fall season has been wet east of the mountains, and much more mixed west of here. Wolf Creek seems to have benefited the most from early season snows so far, but that has been typical for many years.
If this El Niño sticks around until next spring -- and I put the odds for that above 50 percent -- we should have better-than-average odds for a snowy spring, so spring break might be the best skiing conditions of the season, and ski resorts that are more flexible about their closing date should monitor the situation to see whether it might be worth it to extend the season beyond their traditional closing dates.
The last few El Niño events (2002-03, '04-05, and '06-07) have been somewhat unusual in their behavior and impacts, so there is more uncertainty about the spring forecast in particular than we would have back in the 1980s and '90s.
On the Edge: What other areas might get above-average snow in North America this winter? Why?
Wolter: Late fall snow patterns in the Pacific Northwest can go either way with El Niño, and they have been lucky so far -- especially at Whistler -- with the amounts of snow they have been getting. The late winter season tends to be drier than average for that region. On the other hand, New Mexico tends to get more snow with an El Niño winter, and the eastern seaboard has a better chance for heavy snowstorms late in the winter that can give the lower elevation ski resorts in the Appalachians a boost. Both of these regions benefit from the enhanced southern storm track that often develops with an El Niño that takes storms from southern California through the southern states, and often ends up moving up along the eastern seaboard.
On the Edge: What's the most significant weather event of your career? What stands out?
Wolter: I live above Jamestown at 8,500 feet, and the October 1997 snowstorm dropped more than four feet of powder on our house teaching me that even a big snowstorm like that can produce fluffy powder snow rather than the more typical heavy wet snow that we often associate with Four Corners' lows. Last month repeated that lesson, to the tune of three feet.
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But as a winter weather fan, I have to single out the cold snap of early February 1989 (my first winter here) when the Front Range experienced one of its coldest arctic air masses on record (-24 degrees F in Boulder is a record for February), while overrunning Pacific moisture kept us snowing for a couple of days (more than a foot of snow in Boulder Canyon where I lived back then) while staying subzero all the time -- it does not get much more wintry than that!
On the Edge: For someone who knows so much about snow, I'm curious if you ski or otherwise get outside in the winter. If so, what's your favorite area?
Wolter: Yes, I cross-country ski right behind our house in good winters, and I downhill ski with my wife and two sons whenever we have a chance. My younger son is in 5th grade, so we hope to take advantage of the free ski pass he is getting this winter, especially later this season. We don't particularly enjoy driving I-70, so we like to go a bit off the beaten track and ski at smaller resorts like Monarch, for instance.