Mountain Nature and Culture Podcast
About This Show
This podcast explores the natural and human history of the Canadian Rockies as well as its attractions and culture. We'll look at the ecology and wildlife as well as the unique plants and birds that make the Canadian Rockies home. Looking back through our history we will share the stories behind the scenery. This is the place for all things Rockies.
Most Recent Episode
032 Microburst Mayhem and Climate Science in Mountain Landscapes
4 days ago
Microburst Mayhem On the evening of June 8, I was getting ready to head out to the climate change presentation that I'll play during the second portion of this episode, and wouldn't you know it, minutes before I left the house, an extremely severe storm hit Canmore. It postponed the presentation slightly as traffic slowed to a halt and audience members were delayed. Little did I know that a little further west, along the Bow Valley Parkway in Banff National Park, a massive microburst was creating mayhem near to the Johnston Canyon campground and chalets. A microburst hits like a weather bomb. A wet microburst hits like a tornado but lacks the rotational movement. Think of it as a super intense downdraft of sinking air that hits the ground like a hammer. These downdrafts usually come with mind-boggling amounts of moisture and winds in excess of 100 km/hour. Like a tornado, microbursts are extremely local events, usually only affecting a few 100 metres to a few kilometres in size. Climatologists have defined them as extreme downbursts that extend no more than 4 km over the surface. It's small scale, results in much higher wind speeds. They're caused by a huge change in air pressure and the air picks up speed as it descends. Essentially, when a large storm happens, dry air draws moisture from the wet air. This cools the wet air and it begins to sink. The bigger the difference in moisture, the bigger the difference in the air pressure. This cool, low-pressure air drops like a stone. As the downdraft descends, it accelerates. When it hits the ground, it bursts outward and accelerates even faster increasing the potential for damage from the high winds even more. In this particular case, the epicentre was just east of Johnston Canyon along the Bow Valley Parkway in Banff. When I visited on Monday, I explored a little of the impact zone and it was absolutely impassable. Almost every tree was either snapped off or uprooted within an area covering almost 10 hectares. When the storm hit around 5 pm, the debris began flying almost immediately. While the burst was focused primarily east of the campground and resort, a number of trees damaged 90-year-old cabins at Johnston Canyon Resort. In the campground, falling trees caused the evacuation of 100 campers from the Johnston Canyon Campground to Tunnel Mountain in Banff for safety. The storm took out power lines and dozens o