The health of our waters is the principal measure of how we live on the land — Luna Leopold
Weak #LaNiña in the forecast: Here’s what it means for ski season in Summit County — The Summit Daily #ENSO #BlueRiver #ColoradoRiver #COriver #aridification
A nice storm blew through last night. The webcam at Black Mountain Lodge shows a little bit of snow up on the hill. Like earlier dustings, this snow won’t last. We have a sunny week forecast, but temperatures won’t be quite as warm. We should see highs in the 50’s and low 60’s. Not quite snowmaking weather yet, but that time isn’t too far away. Photo credit: Arapahoe Basin Ski Area
As the ski season approaches, everyone wants to know how much snow Summit County will get this year.
Joel Gratz, founding meteorologist of Open Snow, explained that at this point in the year, the only way to have some sort of idea about what the upcoming season will look like is to determine whether it will be an El Nino or a La Nina year and then to look at past weather patterns associated with those climate phenomena. El Nino and La Nina refer to warmer or cooler water temperatures, respectively, in the Pacific Ocean and impact weather worldwide.
“The reason people talk about it now is because El Nino and La Nina is the only factor that we can kind of reliably predict many months in advance,” Gratz said. “All the other things that control storm tracks aren’t able to be predicted more than really a week or two in advance, which is when we’re just tracking each individual storm.”
This year, there’s a 70% to 80% chance that La Nina will arrive this winter, and models are showing that La Nina will be weak to moderate.
So what does this mean for our ski season? Unfortunately, not much.
Gratz explained that the stronger the La Nina or El Nino, the better chance Colorado will get at least average snowfall — if not above average. But a weak La Nina means anything could happen…
Here are the typical outcomes from both El Niño and La Niña for the US. Note each El Niño and La Niña can present differently, these are just the average impacts. Graphic credit: NWS Salt Lake City office
Typically, Gratz said La Nina does well for the Pacific Northwest and northern Rocky Mountains, meaning it’s likely to be wetter than normal in those areas. On the flip side, El Nino often favors the south in terms of precipitation. However, as Colorado is in the middle of North America, correlation between weather and El Nino and La Nina is weaker. Gratz said El Nino often means some bigger storms are seen on the Front Range, but Summit County is often unaffected.
“Many past seasons with a La Nina have done pretty well in the northern mountains where Summit is. Last season was a La Nina, and it was OK but generally below average,” Gratz said…
To complicate things more, Gratz noted that Colorado’s worst season and its best season in the past 30 years both occurred when there was neither a La Nina nor an El Nino. Overall, Gratz said El Nino and La Nina are general concepts that sometimes work at the local level…
The seven- to 10-days out marker is for when meteorologists have their eye on an incoming storm but don’t have many details, Gratz explained. After that, they’re filling in those details, such as snow accumulation ranges, until the storm hits.
While it’s essentially anyone’s guess what the ski season will look like in terms of powder days, the National Weather Service’s two week forecast isn’t promising. Treste Huse, a senior hydrologist for the National Weather Service, said that through the end of the month, above normal temperatures are expected. She added that there is a high chance that the remainder of September will be dry.
