Driving Larimer County's canyons: the one weather tip worth knowing

The canyon drive west of Loveland and Estes Park along U.S. Route 34 is a Front Range favorite: steep red walls, the Big Thompson River alongside the road, and an easy route up to the mountains. Along the way you may notice flash-flood warning signs, and there is one simple tip behind them that is good to plan for: in a flash flood, get out of the low ground and climb.

The reason these canyons take the warning seriously goes back to 1976, when a slow-moving summer storm dropped a huge amount of rain above Big Thompson Canyon. The narrow canyon funneled that water into a wall of flooding that swept down along U.S. Route 34 at night, with great loss of life and heavy damage to homes, roads, and vehicles. State geologists and federal scientists studied it closely afterward, and it remains a key example of how a steep, narrow canyon behaves in heavy rain.

So here is what to plan for. The National Weather Service’s flood-safety guidance is the same: a car is not a safe place in a flash flood. Water can rise faster than you can drive out, so the safe move is to leave the vehicle and get to higher ground, away from the streambed. Steep, recently burned slopes can make this worse, because they shed water and debris quickly. Most days this is just good background knowledge, not a worry.

To learn more about the 1976 flood and the canyon flood hazard, see the Colorado Geological Survey and U.S. Geological Survey reports on the event, and the National Weather Service’s flood safety pages for current guidance.