Harn Sillars 1

Buena Vista’s Mal Sillars, meteorologist and NWS observer, gave a presentation on backcountry weather considerations and reading weather signs March 16.

The CCSAR-N building was full to the brim with interested attendees.

The presentation, hosted by Chaffee County Search and Rescue North and the Buena Vista Public Library, was geared toward backcountry explorers of all levels.

Sillars first put the presentation together for the Upper Arkansas Wilderness Volunteers and later began sharing it with SAR as part of their training.

“This is really the first public event,” Sillars said. “Search and Rescue has called me every year since then as part of their spring academy training, so what I do is basically for new members.”

The idea for the event and the partnership with the library, Sillars said, came from Gina Lucrezi, training director for CCSAR-N.

“She must have talked to somebody at the library,” he aid. “It was not long after I gave my presentation here that I heard from Sarah (Greenberg).”

The event did prove popular – it was standing-room only – and attendees sat with rapt attention throughout and asked questions as the presentation wrapped. Attendees brought a wide range of experience, as well, with some able to identify specific places on trails where Sillars had taken photos.

“I wasn’t sure there were gonna be that many people but it was a nice mix,” Sillars said, “apparently from different areas.”

One of the main features of Sillars’ presentation was understanding how to prepare for changes at higher altitudes, whether due to increased sun exposure, thinner air or unexpected stormy conditions.

Though oxygen remains at 20.9% concentration at any altitude, pressure changes higher up lead to a lower effective oxygen percentage.

The 14ers also have the highest UV index rating of the lower 48, beating even the Virgin Islands. Snow burn is also common in the mountains.

“That’s why you lather up,” Sillars said. “UV increases about 5% for every 1,000 feet of elevation. Here in town, it’s about 40% higher than at sea level, and Longs Peak, which could be any of ours, is 71%.”

Mountain shapes and pressure patterns can determine where major showers will take place due to orographic lifting, in which wind crosses the divide by going up and over the range.

“Think of that divide as one huge, huge snow fence,” he said. “That’s essentially how Monarch does it. They don’t make snow, but they’re right in the right place to get the dumps due to orographic lifting.”

Lastly, Sillars explained how to read cloud formations to better predict and prepare for storms. Cirrus clouds, which are light and wispy and sit very high above the earth, usually portend fair weather.

“Watch for the towers,” he said of building cumulus clouds. “There’s enough instability evidently to get some building going. … This is my rule of thumb. If it looks scary, act accordingly. Don’t try to tough it out. Mother Nature will win.”

He also advised attendees that showers can be short. Overall, persistence is the best forecast for short- and mid-term conditions.

“If you’re hiking and you’ve ever had a shower, showers typically last about 20 minutes,” he said. “Typically, you can figure if you get caught in a shower, if you can make it work for 20 minutes you’re probably gonna be good. … Hear thunder, head down. That’s the old adage.”

Overall, Sillars encouraged attendees to check as many forecast and weather resources as possible before they head out.

The National Weather Service and other organizations have radars and meteorological maps available to prepare for trips, and Sillars said that having more experience and awareness of conditions can make trips easier. High-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE), as well as other forms of altitude sickness, are possible as low as 8,000 feet.

“That doesn’t really affect us that much because we’re here, we’re accustomed to it. Our bodies are climatized,” he said. “But for somebody coming in from the outside who happens to fly into Denver one day and drive here the next morning, these are the folks that are up for that possibility.”

For more information about CCSAR-N, visit http://chaffeecountysarnorth.org/. NWS resources can be found at https://www.weather.gov/