If you were out driving around Wednesday afternoon, you may have noticed a smoke plume or two in the distance. The lack of significant rainfall over the past couple weeks combined with a very dry air mass and sunny skies made for easy burning during the afternoon. As a result, many fires were observed throughout the area.
Many of the fires are what we call prescribed, or controlled burns. These are intentional fires set by Federal, State or Local officials for land management purposes. Other fires are the result of private land owners burning brush or dead grasses. Some of these could have also been wildfires that were started accidentally. Releative humidities Wednesday dropped below 20 percent. This is very low and can be dangerous. Under these conditions, fires can easily get out of control if those burning don't pay close attention to wind direction and speed. Light dead fuels, like grasses, can catch fire very quickly and cause a contained fire to get out of control very quickly, especially under windy conditions.
The image below is courtesy of NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) and shows the local "hot spots" late Wednesday afternoon from fires. Click on the image to be redirected to the NESDIS Fire Products website.
The image below is a radar loop showing the smoke plumes popping up throughout the area. The smoke particles return energy back to the radar just as raindrops or hail from thunderstorms would.
The image below depicts a specific IR (infrared) satellite band that can detect local hot spots from burning fires. Because of the satellite's resolution, only the larger fires can be seen from space. Even then, in this case, these hot spots only show up as having a temperature of 70 to 105 degrees Fahrenheit. Obviously, these fires are much hotter than that temperature range, but the heat from the fire is being averaged with the surrounding non burning areas (which were in the 50s and 60s Wednesday).
Finally, below is a MODIS true color visible satellite image (250m resolution). Given the cloud cover in Wisconsin and the timing of the satellite's passage, smoke plumes are not readily visible in Wisconsin. However, a smoke plume can easily be seen in the Mississippi River Valley. Notice the brown landscape in this image...showing that our local vegetation is still dry and dormant. This image is courtesy of CIMSS/SSEC (University of Wisconsin-Madison).