Montana Blow-down

November 03, 2012


Photographer: Rod Benson; Rod's Web site
Summary Author: Rod Benson
Hunters and hikers who visit the Thunderbolt Creek drainage in central Montana, 20 mi (32 km) north of Butte, are treated to great scenery as they wander the forests and meadows in the shadow of the Continental Divide. But, perhaps the most memorable sight is the incredible area of trees blown down by a straight-line wind event in 1999. This "blow-down", which spans 55 acres, is covered with mature Lodgepole pines that were uprooted and laid flat. They're all pointing in the same direction as though a giant steam roller had passed over them. Although Montana does have an occasional tornado, the similar orientation of the pines near Thunderbolt Creek proves that they were felled by a weather phenomenon known as a "microburst". If it had been a tornado, the damage pattern would have been much more chaotic, with trees scattered and twisted by the tornado's spiraling winds. When air cooled by the evaporation of rain plunges toward the ground, surface winds can reach 150 mph (240 km/h), easily strong enough to blow fully-grown pine trees over. Fortunately, it seems there were no injuries as this area is quite remote.

Photo details: Camera Maker: KONICA MINOLTA; Camera Model: DiMAGE Z6; Focal Length: 5.859375mm (35mm equivalent: 35mm); Aperture: f/8.0; Exposure Time: 0.013 s (1/80); ISO equiv: 50; Exposure Bias: none; Metering Mode: Matrix; Exposure: Landscape Mode; White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB; Software: DiMAGE Z6 v1.00.