A strong atmospheric river brought heavy rain with widespread flooding on the 8th and 9th. There was a period of snow on the 7th, as well as freezing rain in some lower valleys into the morning of the 8th.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS REV wrote it up.
A strong atmospheric river brought heavy rain with widespread flooding on the 8th and 9th. There was a period of snow on the 7th, as well as freezing rain in some lower valleys into the morning of the 8th. Pre-emptive planning caused the closure of public schools and courts in Washoe County on the 9th. Many roads were closed due to flooding, overwhelmed and blocked culverts, and debris flows in the Reno-Sparks, Carson City, and Minden areas on the 8th. A damage estimate from Washoe County Emergency Management for the entire county in January was over $15M, with much of the damage between the 7th and 9th. In Storey County, a damage estimate from flooding and snow in January was $6M for public infrastructure.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Reno, NV wrote its last area forecast discussion before the first event at Jan 7, 3:34 AM PST, 2 hours 26 minutes earlier.
Area Forecast Discussion
National Weather Service Reno NV
334 AM PST Sat Jan 7 2017
.SYNOPSIS...
Snow with possible freezing rain today will transition to heavy
rain and heavy mountain snow in most areas tonight, with extreme
amounts of rain Sunday through early Monday. Significant flooding
is expected for mainstem rivers, creeks, and streams Sunday into
Monday. Another atmospheric river event is looking likely for the
middle of next week with a couple of colder storms to follow the
end of next week.
&&
.SHORT TERM...
* Today, precip starting as snow, then changing to rain in most
areas.
* Possible freezing rain in some colder valleys today-tonight,
with greatest risk north and east of Susanville-Lovelock.
* Intense rainfall with flooding expected Sunday-Monday. Finish
preparations now!
* Several feet of additional snow for highest Sierra elevations,
above 9000-10000 feet.
* Poor conditions for travel and outdoor activities this weekend.
All systems are go for the strong atmospheric river event starting
today and continuing into Monday, with the most intense precip
Sunday and Sunday night. Before we get to the heavy rain and
flooding concerns, today will have another another round of
winter precipitation with cold air mass currently in place. Snow
has already begun in northeast CA around Bogard and west of
Susanville as moisture increases on the leading edge of the deep
moisture feed associated with the atmospheric river.
This snow will spread into the remainder of the Sierra and much of
western NV mainly north of US-50 this morning. Snowfall amounts
for Mono County near and west of US-395 will be similar to the
Tahoe zone (8-16 inches thru this evening above 7000 feet) so they
were added to the advisory. Due to the sharply colder surface air
that will be difficult to scour out, snow may persist into the
afternoon around the Reno-Carson-Susanville vicinity eastward to
Fernley-Fallon before warmer air breaks through and changes the
snow to rain. In fact, much of the Tahoe basin is likely to see a
changeover to rain before the Reno area and other valleys in
western NV/northeast CA. We left in a mention of possible freezing
rain along the US-395 corridor, but if any freezing rain occurs
in these areas it would be brief.
Farther north into Pershing and northern Washoe Counties, the
Surprise Valley and far northeast Lassen County, mostly snow is
expected today, followed by a better potential for freezing rain
this evening which could persist overnight, as a very shallow
layer of cold air will be even more difficult to scour out. There
are some breaks in the steady precip areas for part of tonight
which could limit the ice accumulations, but if the cold temps
near the surface fail to surpass the freezing mark before daybreak
Sunday, some of these areas could receive ice accumulations
between 0.10 and 0.20 inch. This weekend is already a poor choice
for non-emergency travel, and adding ice to the mix will make
conditions especially dangerous including I-80 from Lovelock
eastward across central NV.
Aside from these colder valleys, snow levels should rise rather
quickly by this afternoon or tonight as deeper moisture and
warmer air arrives. Snow levels are forecast to peak by early
Sunday morning, then remain steady through Sunday evening. This
will coincide with the most intense precipitation. North of I-80
we're looking at snow levels near 8000 feet, near 9000 feet for
Reno-Carson-Tahoe, and 9000-10000 feet south of US-50 including
Mono County. Snow levels should finally drop again late Sunday
night through Monday, with precip changing back to snow for most
Sierra passes by early-mid morning, and around the Tahoe basin
during the morning or midday. Snow amounts on the back side of
this storm system are difficult to project at this time, as some
of the guidance tries to wind down the heavier precip a little
more quickly, but at least a few inches could accumulate around
lake level in the Tahoe basin. Some snow or snow showers may
return to some western Nevada valleys by Monday evening.
We are holding on to similar precip projections through Monday as
liquid totals along the Sierra Crest through the foothills west
of US-395 could easily reach 6 to 12 inches. Along US-395, rain
totals around 2-4 inches are likely with up to 2 inches possible
for areas to the east. Additional snow totals above the snow line
could easily reach 3 to 8 feet with the character of the snow
being very heavy and wet. Avalanche danger is likely to increase
through the weekend with backcountry activities not recommended.
As far as winds, they will be strong and gusty across ridge
lines, with peak gusts over 100 mph. In lower elevations, winds
are not anticipated to be as strong with gusts mainly around 30
mph. However, stronger gusts above 40 mph are possible at times,
especially on Sunday and Monday. MJD
.LONG TERM...Tuesday to Saturday...
* Atmospheric River with feet of snow possible in the Sierra Jan 10-
11
* Minor nuisance flooding may still be an issue below 6000 feet
The GFS and EC have some differences with regards to the next AR for
Tue-Wed, but the general idea remains the same. This next one will
not be quite as strong, and it will also be colder overall with snow
levels remaining 7000 feet or below. The GFS overall is a little
colder and keeps snow levels below about 6000 feet while the EC
briefly raises them to 6000 feet near the Oregon Border to 7000 feet
for Mono County. Another item that is consistent is that this storm
will bring stronger winds with it, but given the ample moisture and
the thermodynamic/kinematic profiles they shouldn't be excessive.
The Tue-Wed storm is coming in two parts with the first part early
Tuesday and colder before the stronger, wetter and slightly warmer
wave arrives Tuesday night into Wednesday. In fact, with the waves
so close together due to the strong jet, some places in the Sierra
may not see a break in precip once it begins today. Several feet of
snow in the Sierra above 7000 feet still look possible with a couple
feet down to 5500 to 6000 feet. There Will be plenty of precip
below 6000 feet into Western NV as well, but it looks to be mostly
rain. Flooding concerns look to be much less due to the lower
snow levels.
As far as the winds, they will peak Tuesday afternoon with some
gusts 45-55 mph in the valleys possible. As mentioned above, with
the moist airmass and wind profiles, a strong breaking wave looks
unlikely.
A bit of a break is expected Wednesday night with another storm
arriving Thursday-Friday. It looks to be colder, and also not quite
as strong. In fact, the models are keeping the AR signal to the
south of us so it may not be quite as wet as it looked a couple days
ago. Still, some snow is likely for all elevations creating travel
issues with some rain mixing in on the lower valley floors. The
models are now showing the storm track to then lift north next
weekend, giving us a break for at least a couple days if not
longer. Wallmann
&&
.AVIATION...
Strong storm to affect the region through Monday. For today, snow
will spread over all areas this morning with IFR conds thru 19Z.
Then a change to -FZRA is possible for KRNO-KCXP-KTRK until 22Z when
enough warm air moves in to change all precip there to rain. For
KTVL/KMMH, precip will be snow through 18Z, then changeover to plain
rain.
From KSVE-KLOL and the NE, snow will hang on longer, possibly
through 03Z with a longer period of -FZRA. All areas will be rain by
12Z Sun. Until the changeover, runway accumulations of 2-6 inches
are possible on all area terminals with the exception of KNFL/KHTH.
During the day Sunday, we are still expecting heavy rain to affect
all terminals with ponding of water an issue through 06Z, then a
changeover back to snow is possible from 06-12Z for the Sierra
terminals. SFC Winds are not expected to be much of an issue with
peak gusts to 30 kts. There will be mtn wave turbulence, but LLWS is
not expected to be significant due to the heavy precip.
For KRNO, there is the possibility of some flooding from Steamboat
and Dry Creeks backing up on the SE portion of the airport. The best
chance for this occurring is after 21Z Sunday.
More impacts are likely Mon-Wed with periods of rain and snow, with
heavy snow possible for Sierra terminals. LLWS and mtn wave
turbulence are also more likely for the Tuesday period. Wallmann
&&
.HYDROLOGY...
* High confidence in flood impacts similar to the flood of December
31, 2005 along the Susan, Middle Fork Feather, Truckee, Carson,
West Fork Walker and their tributaries.
* High risk for flooding near creeks, streams, urban areas, and
farmland and burn scars.
* Flood preparations should be completed by this afternoon.
* Intense rain arrives Sunday and Sunday night.
Well advertised atmospheric river will move into the region today
with a period of intense rain and high snow levels from late tonight
into Monday morning. Hourly rainfall rates should exceed 0.50 in/hr
at times in the Sierra/Carson Ranges Sunday and Sunday night. Snow
levels will lower on Monday near the end of the event which will end
the flood threat in the mountains, though high flows on the main
stem rivers will continue into Tuesday.
Soils are saturated and based on the response of rivers, creeks,
streams and drainage ditches Wednesday, it won't take much rainfall
to generate flood impacts across the Sierra and western Nevada.
Creeks, streams, urban areas and farmland are at high risk for
flooding late this weekend. Washoe Valley and the Little Valley burn
scar are also likely to have flooding from this event.
Total rainfall amounts from Saturday night through Monday still look
on track with 6-12 inches for areas west of highway 395 including
Mono County, the Tahoe Basin, Lassen County, Plumas County, the
Carson Range and Reno/Carson City foothills. Farther east in the
lower valleys, 2-4" are possible with 1-2" for the highway 95
corridor.
Peak flows are forecast to hit late Sunday afternoon and night for
the Susan, Truckee above Derby Dam, Carson system above Carson City.
Peak flows in the lower reaches of the Truckee, Carson and Middle
Fork of the Feather in Portola should hold off until Monday into
Tuesday as the water drains through the systems.
The recent 4-8 feet of snow in the higher elevations of the Sierra
will play a role by initially absorbing quite a bit of rain with
some melt off possible. Another factor to add to the mix is the
recent snow at elevations below 6000-7000 feet plus the any
additional snow with the initial phase of the system on Saturday
that will melt and run off. Something to keep an eye on, as how this
plays out could impact the severity of the flood impacts. Brong
&&
.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 4 AM PST Sunday NVZ004-005.
Flood Watch from late tonight through Monday afternoon
NVZ002-003.
Winter Weather Advisory until 10 PM PST this evening NVZ002.
Winter Weather Advisory until 4 PM PST this afternoon NVZ003.
Flood Watch from late Sunday night through Tuesday afternoon
NVZ004.
CA...Flood Watch from this evening through late Sunday night CAZ071.
Winter Weather Advisory until 4 AM PST Sunday CAZ071.
Winter Weather Advisory until 4 AM PST Sunday CAZ070.
Flood Watch from late tonight through Monday morning CAZ073.
Winter Weather Advisory until 10 PM PST this evening CAZ073.
Flood Watch from late tonight through Monday afternoon CAZ072.
Winter Weather Advisory until 10 PM PST this evening CAZ072.
&&
For more information from the National Weather Service visit...
http://weather.gov/renoThe national radar mosaic for the moment the first event began.
7 flood, 1 winter weather. Local standard time, as filed.
Freezing rain resulted in 0.1 inches of ice 3 miles west-southwest of Gardnerville.
Around 1300-1400 homes were evacuated in the Quilici area of South Reno due to flooding, likely from the overwhelming of Steamboat Ditch and nearby channels with the exceptionally heavy rainfall. The end timing of the flooding is roughly estimated. NOTE: No information is available regarding damage to homes.
Twenty five structures, including at least 10 homes (one 8-plex and two single-family homes), were damaged by flood waters in Dayton by the morning of the 9th. Flooding of the two single family homes in East Dayton may have been largely due to breaks in ditches and culverts incapable of handling the exceptionally large volume of water. Water depth varied from 6 inches to as much as 3 feet on the south side of the Carson River. Standing flood waters lasted for at least several days after the initial flood surge on the 8th. Schools were closed county-wide on the 9th. The damage estimate from the Lyon County Emergency Manager is considered very low-end and could actually be several million dollars for Dayton alone. In February, a Federal Disaster Declaration was approved for the January flooding.
Flooding from Steamboat Creek and the North Truckee Drain (near I-80 in Sparks) combined with some input from the Truckee River to bring a large area of lowland flooding between McCarran Blvd and Hidden Valley, as well as south of Interstate 80 in the Sparks Industrial area. Several days of notice allowed many businesses and homes in Hidden Valley (near Boynton Slough) to prepare flood mitigation measures including sandbagging. However, several homes in Hidden Valley still had flood damage due to overtopped sandbags and/or basement flooding. The timing of the flood is approximate and the damage is roughly estimated.
Highway 446 was destroyed by flood waters in more than 10 places on the southwest side of Pyramid Lake. Some sections were left with nearly 50-foot deep ravines. The highway was not re-opened to the public until early March. Repair cost based on Nevada Department of Transportation estimates from Reno-Gazette Journal article in February.
Six Mile Canyon Road was closed due to washouts and heavy damage. The cost to repair the damage is an estimate by the Storey County Public Works Director via a KTVN news article from April.
A bridge over Long Valley Creek in Lockwood was washed out after about 18 hours of moderate to heavy rain. The cost to repair the bridge is roughly estimated.
Kingsbury Grade (Highway 207) was closed due to a previously-repaired (in December 2016) sinkhole re-opening with the heavy rain. The damage estimate is based on the contracts awarded for repairing both the December and January incidents.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nevada in 2017Every state in 2017This day in weather historyWarnings in Nevada, January 2017
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 692958, 693377, 693193, 693321, 693192, 693183, 693179, 693380.