DENVER – When Colorado’s historic rains fell last September, help came quickly.
Resources went to areas that needed it most thanks, in part, to the innovative work of the Federal Emergency Management Agency’s Region VIII Geospatial Information Systems (GIS) unit in Denver.
The GIS team pushed out a steady stream of critical spreadsheets, maps and updates by coordinating with local, state and federal agencies. The team had at its disposal satellite imagery so precise it showed the sediment lines of battered neighborhoods. They used this information to determine locations where the Civil Air Patrol as well as other aircrafts should conduct flyovers to take photos to get additional awareness.
Then the six-member team combined the numerous images with information from the National Weather Service, flood modeling and sources nearest the inundation. The result was a geospatial disaster impact assessment that helped identify communities with the greatest impacts.
“During response we use GIS to estimate impacts to people, buildings, and infrastructure’’ said Jesse Rozelle, GIS coordinator for Region VIII. “We used all of the information to provide situational awareness for decision makers.’’
The team was working almost immediately as the rains began to fall, helping to identify potentially threatened areas. Following the disaster declaration issued by President Obama, the focus shifted to response and recovery, with plenty of work still ahead for the GIS unit. Five days of rain had caused flooding in areas and ways not typically expected.
“The flooding wasn’t always contained within the banks of the river or stream,’’ said Nikki Robles, a risk analyst on the GIS team. “There was a lot of debris in this event which elevated the impacts to people and their property.’’
Although hampered initially by two weeks of thick cloud cover, the GIS unit was able to create increasingly complex products with the addition of yet another tool – LIDAR, which stands for light detection and ranging. LIDAR is a remote sensing method that uses light in the form of a pulsed laser to measure variable distances to the Earth. It generates precise, three-dimensional information about surface characteristics.
LIDAR was part of the GIS team’s arsenal when it was called on months later after a high snow pack created a significant spring flood risk to Colorado.
The unit, which was activated as FEMA’s Modeling Task Force, was able to build on its accomplishments during the September 2013 flooding and pinpoint potential problems from remaining debris and changes to the landscape.
Working with the Colorado Water Conservation Board, it developed forecasts for the state identifying newly created chokepoints in rivers and streams – areas where the potential of flooding had changed from previous seasons. This allowed communities and residents to make better decisions when faced with the threat of spring flooding.
Luckily for Colorado, the worst-case scenario did not happen. But not before the FEMA Region VIII GIS team had produced situational awareness reports for several months so those potentially in harm’s way had a more complete picture of what was coming their way.