It is +7ºC in Banff. Over the last week, the warm Chinook winds warmed up the Bow Valley and with that Larry Limestone at the east face of Mount Rundle. But Larry doesn’t look happy. “This is too warm and too early. I don’t want the snow to melt!”
Kelly Crinoid is confused. “What do you want? First it is too cold, now it is too warm!” She enjoys every season and the weather that comes with it. Who doesn’t like a chinook in the middle of winter?
But old Larry Limestone feels different about it. He is much more concerned about his face. “These conditions weather me and slowly erode my rock face.” During the warm chinooks the snow melts and water seeps deep into the many cracks in his limestone cliff. But when the temperature drops below 0ºC, mostly during the nights when nobody sees it, the water freezes again and grows bigger. This vicious cycle of water creeping into the tightest corners while thawing, and expanding while freezing and turning into ice again, slowly turns hair-thin cracks into much wider cracks. It always ends dramatically––gravity gets them–– and rocks fall off the cliff. Some are big, others are small.
“I already lost too many pieces to this frost weathering.” Larry looks down at the scree piles that formed in the forest below his cliff. “There is my graveyard of erosion––all the pieces I lost over the years.”