We are in the midst of a lovely autumn. Winter is coming, however, and with it arrives a chance of flooding. Soon nearby mountains should be blanketed in snow. Snow-capped mountains hold water our desert needs, foster recreation and provide a beautiful scene to behold from the warmth of our homes on valley floors. A healthy snowpack is a good thing, but it can be dangerous too.
If warm wet storms move across the Pacific, bringing rain high into our nearby mountains, the snow will melt. Rivers draining the mountains will rise to flood stage. This weather pattern is called a pineapple express or atmospheric river. It caused 15 floods along the Carson, Truckee and Walker Rivers over the last 150 years.
Winter river floods are not the only flood threat to Nevada. A different kind of flooding occurs in late spring through early fall—flash floods.
Shortly after a heavy summer cloudburst, a wall of water can emerge from a local canyon. As the water loses speed, gravel, sand and silt in the flow settle on the gently sloping land at the foot of the mountains. These areas are called alluvial fans. Many urban neighborhoods are built on alluvial fans, and they are vulnerable to inundation by rushing water, mud and debris.
While we can have local flash floods in summer, our biggest floods occur in winter. When they do, all flat low-lying properties near the Carson, Truckee and Walker Rivers are at risk. For this reason, Nevada Flood Awareness Week is held annually in early November.
During this time, the Nevada Flood Awareness Committee will visit area schools to run flood demonstration models with youth. The committee will also offer public educational programs to those of all ages.
Stop by to see flood model demonstrations, visit informational booths and view flood presentations. Learn if your home or workplace is at risk for flooding, how to prepare for flood hazards and the ins and outs of buying flood insurance. Do not wait until flooding is imminent. Become flood aware now.
If a flood occurs this winter, stay safe. Should evacuation seem likely and if it is safe to do so, turn off utilities, fill bathtubs and sinks with clean water, move valuables to higher ground, board up or shutter windows and bring outdoor items inside.
If floodwaters catch you at home, take emergency supplies up to the roof and wait for help. If evacuating by car, bring food, water, medications and family disaster supplies. Do not drive through flooded roadways. If your car stalls in floodwaters, quickly abandon it.
Our beautiful winters do not always produce river flood disasters. Just in case, though, remember to explore flood resources this season. For more information, visit nevadafloods.org or facebook.com/nevadafloods.