Dry conditions and gusty west winds Friday afternoon contributed to a large wildfire developing in the Horicon Marsh, midway between the towns of Horicon and Waupun.
The fire was large enough to show up on the radar at the NWS office just south of Sullivan in eastern Jefferson county. Here is the radar animation showing the start of the fire just after 3 pm, through 5 pm. The fire continued to burn after 5 pm. Wisconsin DNR personnel stated the fire covered 400 acres for a time.
NWS - Milwaukee/Sullivan