From the Mountain Town News (Allen Best):
But what caught the eye of Nolan Doesken and his staff at the Colorado Climate Center was the rainfall patterns. In most such summer rains, the deluge occurs at 7,500 feet in elevation and lower, or in the foothills. This time, rain fell up to the Continental Divide.
“The majority of the water is still from the base of the foothills up to 8,000 feet, according to the U.S. Geological Survey. Our analysis will probably confirm that. But there’s a lot of contribution of elevations above 8,000 feet, which is why water was flowing through Estes Park,” said Doesken, Colorado’s official state climatologist, in an interview on Sept. 19.
“This is pertinent to mountains towns,” Doesken added, “because mountain towns to a certain extent have always been conveniently, climatically immune to the worst of flooding. Estes Park, at an elevation of 7,500, would be at the low end of such mountain towns. Most of the flooding at those elevations has been snow melt caused after blistering sunshine rather than pouring rain.”[…]
But what lessons should be drawn from this rain and flooding along Colorado’s Front Range. The most notable takeaway is that even if this is a 1,000-year rainfall event in certain places, a conclusion not accepted by all meteorologists, the flooding was far less. In Boulder, it fell within the framework of a 50-year flood, maybe less. The flooding of St. Vrain Creek, which so heavily damaged Lyons and Longmont, may have been something approaching a 100-year event…
Many questions remain. How much should a community invest in a 200-year flood event? How much can it afford? Well-heeled Boulder did pretty well handling this 50-year event, but even so there were problems in some residential areas, where water cascaded off slopes. And the flood there in 1894 delivered more than twice as much water, about 13,000 cubic feet per second, as compared to about 5,000 cfs this time…
n my travels during the last two weeks, I only got a glimpse of the great power of this water and the destruction it has wrought —and this is just a 50- or perhaps 100-year flood. I haven’t seen the homes destroyed in Lyons, Longmont and Jamestown, nor the carnage in Big Thompson Canyon. Will people there rebuild again, as they did after the 1976 flood?
As a human species, we tend to forget. We know about flooding, but it’s an intellectual thing, an abstraction. But even when we know it form direct experience, it’s easy too forget after 10, 20, or more years. Much harder yet is imagining a future that’s not quite like anything in our recorded past.