BIG THOMPSON RIVER

The Big Thompson is a small river that drains through the Rocky Mountains National Park eastward through the Front Range Mountains and past the town of Estes Park.

It is a picturesque river which is a favorite haunt of picnickers and campers. Many people also have vacation homes along its banks.

One of the main attractions of the river is the fact that it runs in a gorge so narrow that, in some places the main highway has to be built over it on stilts.

The Big Thompson gets snowmelt from the Rockies each Spring, but this is not of major concern. The main reason for the river's notoriety is the fact that it is subject to devastating summer flash floods. In this it is not alone, because this is a common property of many Front Range rivers. The difference is that the upper Big Thompson is almost circular, meaning that water converges on the trunk channel from the headwaters more quickly than any other river in the area. It is also on the approach road to a national park, making it more densely populated than any other river in the area.

The picture below (of which the top one is from the USGS collection) shows what happened at the end of July 1974 and subsequently.

Many houses were demolished during this flood as well as 144 people losing their lives (most of whom were camping by the river). Insurance money paid for the rebuilding of some properties in just the same places as they were before the floods. This may or may not put the occupants in the same risk as they were in before 1974.

The Big Thompson about 10 years after the flood shown in the picture at the top of this page. Many houses were still precariously poised. Notice the large boulders in the river bed, a sure sign of the potentially disastrous capability of the river to have large flows.

The Big Thompson. These signs were subsequently erected. They may not be of much help to those who do not realise how suddenly a flash flood can arise. In torrential rain people are very reluctant to leave their cars and scramble up a soaking wet bank just in case there is a flood. By the time they see it coming, it is too late. Local broadcasts on the radio are much more effective, as is the closure of the road when danger threatens.