Satellite shows burn scar from Fourmile canyon fire of sept. 2010

Aug 02, 2011 By Michon Scott
Credit: NASA Earth Observatory/Jesse Allen/Robert Simmon/NASA EO-1 team/USGS

In September 2010, the Fourmile Canyon Fire broke out in the foothills west of Boulder, Colorado, scorching more than 6,000 acres (2,500 hectares) and forcing residents to evacuate. Ten months later, residents had to evacuate again, this time to flee floods. Stripped of vegetation, the slopes along Fourmile Canyon soaked up little of the water dropped by a thunderstorm. Instead, the runoff surged into local stream channels.

On June 7, 2011, the Advanced Land Imager (ALI) on ’s Earth Observing-1 (EO-1) satellite observed the Fourmile Canyon burn scar. The image is made from a combination of shortwave infrared and visible light.

The scar is more easily detected in the false-color image, where the burned area appears in shades of red and orange. Creek valleys, which generally escaped the flames in September 2010, form winding corridors of green through the scar. To the east and southeast, the city of Boulder lies on relatively flat land.

After the fire, the U.S. Geological Survey (USGS) warned residents to prepare for the possibility of flooding, even from small rainstorms. Late on July 13, 2011, such a storm occurred. As rain fell west of Boulder, Fourmile Creek rose rapidly. In fact, at one USGS gauge, the water discharge rate skyrocketed in a matter of minutes from 10 cubic feet per second to 350 cubic feet per second. The increased water flow translated into a 4-foot (1.2-meter) surge down the creek. Smaller surges followed later that night and over the next few days.

Fourmile Creek is a tributary of Boulder Creek, which flows eastward through the city. usually peak between mid-May and early July. But thanks to the melting of an unusually heavy snowpack, water levels on Boulder Creek were especially high when the July 13 struck. As residents in the Fourmile burn area were ordered to evacuate low-lying homes, emergency sirens also sounded in Boulder.

By late July 2011, water levels had receded along both the Fourmile and Boulder Creeks, although water levels in both remained above normal. Colorado’s monsoon season typically lasts from about mid-July to early September, so the possibility of more flooding remains.

Because of the angle of sunlight, these images may cause an optical illusion known as relief inversion.

Explore further: A 5.3-million-year record of sea level and temperature

add to favorites email to friend print save as pdf

Related Stories

Colorado's 'Reservoir Road Fire' can be seen from space

Sep 14, 2010

NASA's Aqua satellite flies around the Earth twice a day and captures visible and infrared imagery. On Sept. 12 at 19:20 UTC (3:20 p.m. EDT), the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument ...

NASA images show anatomy of pakistan flood disaster

Aug 23, 2010

In late July 2010, flooding caused by heavy monsoon rains began across several regions of Pakistan. According to the Associated Press, the floods have affected about one-fifth of this country of more than ...

Recommended for you

Image: Grand Canyon geology lessons on view

5 hours ago

The Grand Canyon in northern Arizona is a favorite for astronauts shooting photos from the International Space Station, as well as one of the best-known tourist attractions in the world. The steep walls of ...

First radar vision for Copernicus

5 hours ago

Launched on 3 April, ESA's Sentinel-1A satellite has already delivered its first radar images of Earth. They offer a tantalising glimpse of the kind of operational imagery that this new mission will provide ...

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.