IL

Storm restoration across Jo Daviess County

Jo Daviess County sits in the Driftless Area of extreme northwest Illinois, a glacially unscoured landscape of steep ridges and narrow valleys that channels and accelerates severe weather. The county faces recurring hail events, including golf-ball-sized hail (1.75 in) documented near Rodden in April 2026 and ping-pong-ball-sized hail during the March 2026 outbreak. Straight-line winds and derechos pose a persistent threat: the July 2024 derecho drove measured gusts of 84 mph at Stockton and an estimated 80 mph at Galena, uprooting large-diameter trees and damaging structures across the county. Tornadoes are less frequent but confirmed; the county has logged roughly 20 recorded tornado events since records began, including an EF-1 near Elizabeth in August 2017 and an EF-1 east of The Galena Territory in April 2026, with July the peak month for tornado activity. Flash flooding is a recurring hazard amplified by the Driftless terrain: in September 2024 a Stockton-area station recorded 16.62 inches of rainfall in a single month, and July 2011 brought catastrophic flash flooding across Jo Daviess and neighboring Dubuque County. Winter storms bring heavy snow, ice, and extreme cold, with Stockton recording the coolest county average temperature in Illinois for 2024 and the county-seat of Galena logging a historic low of negative 35 degrees Fahrenheit in February 1996.