Denali mountain weather
What? Overview of weather patterns and climatological trends on Denali from reanalysis and in situ data Why? 1) get a quantitative sense of seasonal trends and shifting weather patterns at altitude on Denali (in the future: support operational forecasting on the mountain) 2) data rescue mission for records from a unique AWS on Denali Pass (1989-2007, 5715m), which -as far as we know- was the world’s highest AWS at the time of installation.
Summary: Denali has a reputation for “bad weather” in the mountaineering community. Unsurprisingly, this is statistically reflected in reanalysis as well as station data. The weather on Denali is very cold and very windy very often. With climate change, it is very cold a bit less often. At the synoptic scale, the polar front is a dominant feature for Denali weather and the position of the polar jet tends to determine how cold and windy it is, exactly. How often certain weather patterns occur changes over time, but it is difficult to link shifts in such patterns to specific causes and more research is needed to fully understand how climate change might affect upper level weather patterns in the region. More here.
Data from an automatic weather station on Denali Pass (operational 1990-2007, with big gaps) provides a unique historic record, mainly of temperatures and wind speed, from the summit region. The installation and much of the maintenance activity at the station was carried out by incredibly dedicated and motivated volunteers without institutional support. The initial installation was motivated by a fatal accident at Denali Pass. Friends and climbing partners of the deceased set out to prove that winds can be so strong at Denali Pass that climbers may be “blown off the mountain”. The extreme wind speeds recorded by the weather station support this claim. Lessons that might be learned from the Denali Pass AWS pertain to the power of motivated individuals and “citizen science”, the need for long term institutional support for long term observational records, meteorological instrumentation for extremely harsh conditions, and data management practices. (Much appreciation for B. Perry who reviewed the AWS paper and is very good at putting weather stations on tall mountains.)
The Denali Pass AWS in 1990 (photo Y. Okura/JAC) and during maintenance expeditions carried out by the UAF team, from 2003 to 2007 (photos T. Saito). 10.1175/JAMC-D-20-0082.1