Data Loggers Track Wildfire Behavior

University of Californial at Davis
A PhD candidate at UC Davis conducting a regional climate study dramatically changed the focus of his research after a wildfire swept through his data logger sites, with several of the loggers surviving the event and providing data that proved extremely helpful in explaining the fire and its behavior.

Jeff Kennedy, a Ph.D. candidate in the Ecology Graduate Group at the University of California at Davis set out to track how topography and soils modulate regional climate and water energy balance in native vegetation.

With the help of seven HOBO Pro RH/Temp data loggers arrayed over a vertical mile of mountainous terrain along the rugged Big Sur Coast of central California, Jeff put his research into high gear.

Unfortunately, on September 21, 1999, a wildfire dramatically changed the course of his future research. The fire, which burned for more than a month, had overrun six of the seven logger sites. Jeff couldn't get Forest Service permission to revisit his sites until October 20th, at which point he retrieved the three loggers that survived.

Much to his amazement, the red LED lights were still flashing, even in the data logger that was encased in a melted radiation shield!* Jeff was able to download a complete data record from these three surviving loggers since the last download on September 10th. Even though the data differed due to the swings in temperature and humidity from being through the fire, on the ground for a month, and then in his home basement, the data values seemed to be valid for the environments in which they were taken.

According to Jeff, "The importance of the data from the HOBO Pro data loggers is that they were able to determine the relative timing of the fire on the two adjacent slopes, and the respective rates and inferred direction of fire spread. Looking at the data, it appears that the hot, dry south-west-facing slopes of Lion Peak burned first as an intense 'head' fire moving rapidly upslope. The nearby northwest-facing slope of Lion Peak, just over the ridge, began to burn 20 to 30 minutes later as a lower intensity 'backing' fire that moved slowly downslope. This information will help to correlate weather conditions and fire behavior along with the severity of the wildfire's impact on the vegetation."

Even though his original research was interrupted, the data retrieved from the damaged HOBO Pros proved extremely helpful in explaining the fire and its behavior. Jeff plans to continue using HOBO loggers to record the necessary data for his original Ph.D. dissertation despite the firedamaged environment.

"The ability of these two data loggers to survive lower intensity, shorter duration wildfires is truly remarkable. Thanks for making such a wonderfully accurate and rugged product!"

For more information about data loggers, please contact Onset at 1-800-LOGGERS, or visit