The Rain Shadow

Living on the east side of the Continental Divide, I reside in what is generously known as the “rain shadow.” In plain English, this means we don’t get much rainfall. The rain shadow effect occurs because the mountains of the Continental Divide, just west of us, essentially rob moisture from the air traveling eastward from the Pacific Coast. As the air rises on the west side of the divide to clear the high mountains, it cools and releases moisture as precipitation, leaving drier air to descend on the eastern side. This results in significantly less rainfall in areas east of the divide, creating a semi-arid climate near Helena, where I live. Among other things, this leaves our region prone to wildfires.

Yesterday, as part of a fire mitigation scheme, a prescribed burn was conducted on a few hundred acres near American Bar, an area perhaps a dozen miles from me as the crow flies. I first noticed an arm of smoke reaching up from the mountains there in mid-morning. The smoke persisted throughout the day but waned toward the evening, which seems to indicate a successful, limited burn to reduce fuel. Hopefully, this is the case.

Living in the rain shadow, you need to accept wildfire as a natural part of what shapes our landscape, but you can never become fully comfortable with it. I am posting a couple of photographs I captured from my house:

Smoke Rising Up in the Distance

Smoke as Seen from my Back Deck

—Mitchell Hegman