Photograph of a flood in 1907
These floods occur when there is significant snowpack in the mountains surrounding Lake Tahoe, and a warm, wet rainstorm from the central Pacific, called a “Pineapple Express” moves into the region. The combination of rain and snowmelt can cause the Truckee River to flood.
The other type of flood is called a tributary flood, which occurs with extreme amounts of rain. Tributaries are the streams and creeks that drain into the Truckee River. During a tributary flood, intense local rain causes stream, creeks and other drainage ways to flood before reaching the river. In these floods, local drainages can experience a 100-year flood while the Truckee River experiences a lesser flood. The 2005 flood was a tributary flood cause by intense rain for a sustained period of time.
On average, the Truckee River experiences about one flood per decade. The worst flood recorded in Reno was in 1955 at the Virginia Street Bridge. The river was flowing at an estimated 20,800 cubic feet per second. For comparison, the 1997 flood flows were 20,700 cubic feet per second. Other floods on the Truckee River occurred in 1861, 1862 (twice), 1897, 1886, 1890, 1907, 1909, 1928, 1937, 1950, 1963 and 1986.
With a substantial history of flooding in Reno, the Virginia Street Bridge will be either restored or replaced to alleviate flood damage to homes, businesses and the citizens of Reno.
Floods over the years have taken a toll on the Virginia Street Bridge. Have a closer look: