Nov 1, 2008 12:00 PM, By Mary Rose Roberts

Environmental sensing technologies are providing earlier warnings of impending natural disasters, improving the ability of public safety to get people out of harm’s way.

The technology has matured and form factors have shrunk. One of the first systems was put together by the U.S. Navy and the Boeing Co., which used multiple racks to hold the receivers that sent out the signals, Smith said. The advent of microprocessors and miniaturized systems reduced the space needed to hold components.

“Remote stations now are typically in cans, 2 inches wide and 8 inches long,” he said. As a result of the smaller form factor, deployment is easier, particularly in rugged, mountainous regions. In fact, remote systems often are installed in high mountain watersheds, and the Colorado Rockies boasts the highest deployment of a master station at 12,000 feet.

NRCS engineers hike, ski or ride helicopters to access and maintain sites, but they don't visit sites very often, Schaefer said. Sites are designed, instead, to operate unattended and without maintenance for a year. Power is supplied by battery that is backed up with a solar-cell recharger. Each site is monitored daily, and if the system senses a deteriorating performance, an alarm is sent to technicians in six data collection offices.

SNOTEL sites are polled by two master stations operated by the NRCS in Boise, Idaho, and Ogden, Utah. Sites have a pressure-sensing snow pillow, storage precipitation gauge and air temperature sensor. Wind speed is sensed every minute during the day to arrive at an average, while the snow pillow is accessed every 15 minutes for the accumulated total. Data are sent to NRCS command centers when a meteor burst occurs.

Schaefer said the stations accommodate 64 data channels and will accept analog, parallel or serial digital sensors. All data received by the SNOTEL central computer are put into a relational database, where various analysis and graphics programs are available.

The NRCS also has developed a marriage with the National Weather Service to alert first responders and residents to floods, heavy winds and rains, avalanches, and other environmental events. Schaefer said software-based alerts can be queued into the system. If an event occurs, the system can send data to mobile devices or the command center. However, the remote stations are always at the mercy of waiting for the master station to pick up a signal from a meteor trail — which could take three to four minutes.

“It's not a real quick response, but within a few minutes the data does get through,” he said. “So it works well with environmental monitoring [applications] where you need a dozen perimeter readings per hour and alerts about major events within 10 or 15 minutes.”

Gathered data are sent hourly directly to the National Weather Service, which then distributes it to its weather forecast centers that are responsible for issuing warnings and watches to the public, Schaefer said.

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