Atmospheric River on its way as Carson City prepares for heavy rain, flooding

Snow showers Saturday turned to a brief period of frozen rain followed by light rain showers in Carson City.

Showers tapered off Saturday afternoon, but the break in precipitation will be short-lived as the much-anticipated atmospheric river event approaches Northwestern Nevada from the Sierra Nevada mountains to the west.

AccuWeather radar shows the major storm system is crossing California to the western slopes of the Sierra Nevada at this hour.

Steady rain is expected to begin falling late Saturday night into Sunday morning with periods of heavy rain throughout the day Sunday in the forecast, according to the National Weather Service (NWS) in Reno.

Rain could begin falling as early as 9 p.m. Saturday night.

Higher temperatures are also forecast, the NWS reports, with Sunday's high of 48 degrees reached at around 5 a.m.

The combination of heavy rains throughout the Reno-Tahoe and Sierra Nevada regions of Northwestern Nevada and Eastern California, combined with snow levels rising dramatically to around 9,000 feet overnight, is setting the stage for a widespread flooding event in communities across the region.

Up to two inches of rain are possible around Carson City Sunday, the NWS said, and winds will pick up from the southwest 15-20 miles per hour (mph). Gusts to 30 mph Sunday.

Another inch or so of rain is possible Sunday night into Monday morning with an overnight low of around 37 degrees.

Rain will continue into Monday but begin to let up Monday night into Tuesday. Daytime highs are expected to reach about 44 degrees Monday and Tuesday with overnight lows around 35 both days.

Though not as heavy as Sunday and Monday, a chance of rain and/or snow persists in the region until Saturday, the NWS forecasts.

According to the NWS, the atmospheric river phenomenon will produce periods of intense rainfall, pushing snow levels as high as 9,000 feet. Rainfall totals between Sunday and Monday could reach between six and 12 inches total accumulation in the foothills above Carson City, while between two and four inches of rain are expected to fall in Carson City and other surrounding valleys.

The NWS said the combination of intense rainfall on saturated soils and melting snow will lead to excessive run-off. Flooding is anticipated along the east and west forks of the Carson River, the NWS reported.

Travel may be very difficult with water covering some roads, as well as the potential for rock and mud slides blocking roadways in areas.

The Carson River is currently below flood stage at around four feet. But this is expected to change rapidly between 6 p.m. Saturday and 6 p.m. Sunday, the NWS reports, as water level crests to 11 feet in that time. Waters of the Carson River reach flood stage when they crest 10 feet, according to the NWS. By 6 p.m. Sunday, the river's level is forecast to be more than 11 feet, qualifying as a major flood event.

Major flooding for the area is defined by the NWS as impacting many roads, highways, homes and structures from Genoa at the foot of the Carson Range to Fort Churchill in the east, affecting the communities of Carson City, Stewart and Dayton in between.

During a major flood event, tranportation becomes difficult, closing major highways in the area. According to the NWS, massive bank erosion is possible with the capability of washing away buildings, roads, and heavy machinery. The river channel begins to move around laterally at about 10,900 cubic feet per second.

Carson City, Douglas and Lyon counties have each made declarations of emergency to the state of Nevada in anticipation of the impending flood event.

A rapid response strike team, comprised of multiple city departments, has been assembled and is in place ready to go at the Carson City Emergency Operations Center.

Team members are working closely with the State Emergency Operation Center, neighboring jurisdictions and community partners to ensure timely response related to the Coattail Storm. Resources are being staged strategically throughout Carson City so responders can quickly assist citizens as incidents arise.

An evacuation center — staff by volunteers with the American Red Cross, the Carson City Salvation Army, and the Latter-Day Saints Church of Carson City — has been established at the LDS Church located at 411 S. Saliman Road, just south of Carson High School. The evacuation center is up and running, ready to assist residents experiencing power outages from heavy rainfall or help with flood-related events.

Carson City Emergency Management encourages residents to visit www.carson.org/flood to stay up-to-date on road closures, floods, and resources being deployed across the city. In addition, all official public information will be posted to the flood site.

A Flood Hotline has also been designated for flood-related reporting and questions, which are not life-threatening. The number is (775) 887-2355 and officials recommend the public to use this number instead of 9-1-1 for non-emergency flood calls.

Current incident information can be found at www.carson.org/flood.

Social media users are encouraged to share information related to the event using the official hashtag #NVFlood17. Emergency Management will be monitoring the hashtag in order to maintain situational awareness of what is occurring throughout the City.

Although school starts in Carson City the week of Jan. 9, the school district web site shows there is no school Monday due to all-day professional staff development. Classes are scheduled to resume Tuesday, Jan. 10.

For information on how the flood event may affect Tuesday's classes, visit the Carson City School District web site here, or call the district office at (775) 283-2000.