Come Hell or High Water

[ghost7]

CNRFC Daily Briefing (noaa.gov) Wed Dec 20, 2023 9:55 AM PST

Summary:

• An upper level low off of CA coast currently near the Bay Area moves south into Thursday then inland over Baja Friday bringing precip, especially along the coast and transverse mountains. Highest totals are expected over coastal areas and along the transverse mountains especially in Santa Barbara and Ventura Counties. Freezing levels generally 7000 ft and higher.
• A trough moves through the Pac NW and digs into the Great Basin Friday into Saturday for possible precip over the north and Nevada. Another system moves into the Pac NW Sunday into Monday for possible precip over Srn OR and Nrn CA.
• Moderate river rises are expected through Friday in California coastal and mountain regions as a storm system moves across the state, with major rises in some southern CA rivers.
• Flood stage is expected at the Ventura River at Ventura, monitor stages at a couple other southern CA locations as well as the Sacramento River at Rio Vista at high tide.

Detailed Hydrometeorological Discussion: cnrfc.noaa.gov/discussion

It’s just been chins in the wind for Ventura County all year long.

[ghost7]

LACoFD Technical Operations provides a well-produced intro to the fundamental elements of a Swift Water Incident, IC priorities and resource deployment factors.

“Swiftwater Command”, May 13, 2020

Swiftwater Command

[ghost7]

Ventura River Update: On Thursday, Dec 21st, rain over 1"/hr inundated roadways in Oxnard, Port Hueneme, a freeway ramp in Santa Barbara, and several blocks of mixed residential and commercial structures over the impacted region. The Ventura River crested at a little over 10 feet in the afternoon. An individual was rescued by hoist from the river bottom by Ventura City FD using an aerial ladder truck and ropes.

Overall, dramatic fall rates were recorded at several locations, but mitigation work (several outfits, including CalGuard engineers) and the particular pattern of this storm contributed to a relatively mild impact on the instrument at Foster Park. The area is generally expected to have a week to ten days of runoff before the next storm.

Anecdotally, the nearby Carpinteria gage is undergoing trigger point review for monitor and flood stage alerts.

[Flyron]

SoCal Rainfall

Storm system brought significant rainfall to parts of SoCal

[ghost7]

California’s flooding rains and heavy snows that killed at least 17 people have likely caused more than $30 billion in damages and economic losses, according to AccuWeather Inc.

The Pacific storms, known as atmospheric rivers, are estimated to have caused $31 billion to $34 billion of economic impacts through major flooding, widespread power outages, landslides, fallen trees and road closures, the commercial weather forecaster said…

California Storm Losses Estimated at More Than $30 Billion

I see a wide range of estimates out there, but there are a lot of factors to consider before landing on a very specific number because of confounding issues; including stalled Federal budgets and wage increases, unresolved liability disputes and international turmoil which impacts trade.

[ghost7]

USGS Water Dashboard Jan 10 2024

Major flooding across the Eastern Seaboard. Winter Storm Finn is forecast to continue having major impacts into the weekend. I don’t have solid intel, but I’d suppose there’s a fairly high number of IMT and USAR deployments going on.

5 Day Precipitation Forecast

[ghost7]

Summary:

• Rounds of precipitation for most of the region this afternoon into early next week as several waves move through under moist westerly flow.
• The first wave will bring precip this afternoon through Saturday and the next more widespread system arrives Sunday through Monday.
• Freezing levels generally around 5500-7500ft over the weekend into early next week.
• Northern and Central California rivers will see increased flows beginning early Saturday, peaking at most locations on Sunday and Monday.
• Over the next 5 days, exceedance of flood stage is forecast on the Russian River at Hopland, and exceedance of monitor stage is forecast at several locations along the north coast and Sacramento River system.
• Weir flow is expected along the Sacramento River at Colusa and Tisdale weir. Forecasts are just below the weir crests at Moulton and Fremont weir.

Confidence: Medium

Staffing Level: Normal

Detailed Hydrometeorological Discussion: cnrfc.noaa.gov/discussion

Winter Storm Watches in the Sierra. Dense fog in the lower Central Valley. Flood Watches in place for the Russian River valley and surrounding areas.

Hydrological Outlooks for the SF Bay Area and Monterey County.

USGS instrumentation throughout the San Francisco Bay Area
indicates that shallow soils on steep hillslopes are
approaching saturation. This coupled with the forecasted
precipitation means widespread shallow landslides are likely.

Full Text: NWS Alerts (weather.gov)

Update: Fri Jan 19 2024 11:30 AM PT

Flood Watch issued January 19 at 9:41AM PST until January 23 at 4:00AM PST by NWS Sacramento CA

A series of warm weather systems will bring heavy rain to interior
California this weekend. The heaviest rain is expected Sunday night
and early Monday morning. This will cause significant rises to small
streams, including possible flooding, especially for streams
draining from the foothills into the Valley.

• WHAT…Flooding caused by excessive rainfall is possible.

• WHERE…A portion of northern California, including the following
  areas, Central Sacramento Valley, Motherlode, Mountains
  Southwestern Shasta County to Western Colusa County, Northeast
  Foothills/Sacramento Valley, Northern Sacramento Valley and
  Southern Sacramento Valley.

• WHEN…From Sunday afternoon through late Monday night.

• IMPACTS…Excessive runoff may result in flooding of rivers,
  creeks, streams, and other low-lying and flood-prone locations.
  Creeks and streams may rise out of their banks. Flooding may occur
  in poor drainage and urban areas. Low-water crossings may be
  flooded. Storm drains and ditches may become clogged with debris.

• ADDITIONAL DETAILS…

• Urban and small stream flooding from prolonged heavy rain
  through Monday. Cottonwood and Cow creeks over Shasta county
  and Battle creek over Butte county may be at higher risk for
  flooding.
• http://www.weather.gov/safety/flood
  Instructions
  You should monitor later forecasts and be alert for possible Flood
  Warnings. Those living in areas prone to flooding should be prepared
  to take action should flooding develop.

[ghost7]

[Flyron]

California: Rockslide blocking road cleared with explosives

[ghost7]

Summary:

• Moderate to locally heavy precip today through Monday.
• Freezing levels generally around 5500-8500ft into early next week.
• Highest precip amounts over the north coast, CA coastal mountains, and the Sierra.
• Additional systems to bring precip to nrn CA mid to late next week.
• Northern and Central California rivers will see flows holding near current levels, with additional rises expected last Sunday into Monday.
• Over the next 5 days, exceedance of flood stage is forecast on the Russian River at Hopland, and exceedance of monitor stage is forecast at several locations along the north coast and the Sacramento River system.
• Weir flow is expected along the Sacramento River at Colusa and Tisdale Weir.

Confidence: Medium

Staffing Level: Normal

Detailed Hydrometeorological Discussion: cnrfc.noaa.gov/discussion

Nothing too alarming so far. Hopland is looking at a crest tonight of 15.1 ft, just into Minor Flood stage.

Here’s a comparison to last year at Healdsburg, for reference.

I have nothing about debris flows from last year’s fires, but they had pretty lively weather all year, so I’d imagine an abundance of caution is called for.

Sacramento upper valley and foothills. The Trinity River is running high, but there is yet a lot of capacity at Shasta and in the system southwards. Flash floods are the thing. Mostly small creeks, steep inclines, known low-level crossings, etc. As was noted by NWS for the Bay Area and Central Coast, and is probably getting to that point in the year for other regions, some of the grounds are reaching soil saturation levels, increasing the risk for slides. Naturally, there will be a lot of eyes on the levees, especially the newer works and known problem spots.

[ghost7]

Mon Jan 22 2024 7:30AM PT

Flood Warnings: Russian River southwest of Healdsburg, Laguna de Santa Rosa in Sonoma County. Alameda Creek in the East Bay. Half Moon Bay and the Santa Cruz Mountains.

Watches for the 'Dino, OC, Oceanside, Cleveland NF and San Diego County.

[Flyron]

**GOES-19 Wx Satellite **

https://www.axios.com/local/denver/2024/01/22/colorado-weather-satellite-kennedy-space-center-goes-u

[ghost7]

Offshore winds and upwells wrung the clouds against elevations of 1000+ ft in a few miles between Gillespie Field, La Mesa and Lemon Grove for 5" of rain within a few hours on the San Diego River Watershed and Estuary, sand and gravel aquafers under river that quickly overwhelmed the system, with little catchment on the downhill side. The river’s course meets the separate aquafer buffer south of Fashion Valley with an elevation line between.

[ghost7]

What happened on the San Diego River last week reminds me a lot of topological alignment during a fire, where you get a run because the wind, elevation and topology align in parallel with the fire’s spread.

Rough analogy, I guess, with how the precipitation fell directly into the watershed.

Except that Pacific storms have been carving the coastal mountains to fit for a very long time.

[ghost7]

Summary:

• Dry and warm conditions into early Tuesday except a few showers possible over ther far north this morning. Temperatures around 5 to 20 degrees above normal with some recrod high max and high min temps possible.
• More widespread precip expected late Tuesday through Thursday as system moves through the region with showers lingering into Friday with trough over the region. Freezing levels around 9000 ft and higher on Tuesday then falling behind the cold front to around 3500-5500 ft over Nrn and Central CA by early Thursday and 4000-6000 ft over Srn CA and NV by Friday morning and down to around 1500-3000 ft over Nrn and Central CA Friday night.
• Significant rises are expected towards the middle of the week when a stronger storm is expected to impact much of California. Rivers will be highest along the north coast and Sacramento River system.
• The Colusa Weir and Tisdale Weir are expected to flow again this week, with the possiblity of Moulton Weir and Fremont Weir flow later in the week.
• Low level snow will continue to melt in advance of the storm system, but will have little impact on river levels.

Confidence: Medium

Staffing Level: Normal

Detailed Hydrometeorological Discussion: cnrfc.noaa.gov/discussion

Be aware that CAL OES is weighing in on social media about misinformation regarding expected impacts of this storm system and that impacts are forecast to be moderate. It appears that a few social media accounts are on an ARKStorm ride. This storm system is not projected to be of that magnitude.

Projected 5-Day total precipitation.

Flash flooding is as often a case of inches per hour as total rainfall over the course of a storm. These maps do not reflect those potential inches per hour numbers, that can be very localized, and have unexpected impacts in the watersheds they fall on.

[Flyron]

Two more atmospheric rivers take aim at California, Northwest bringing flood...

[ghost7]

British Columbia’s River Forecast Centre issued an upgraded flood warning for the Sumas River, a tributary of the Fraser River east of Vancouver on Sunday.

An updated bulletin says flows in the Sumas River are not anticipated to pose a hazard for flooding into Sumas Prairie, an area that was hard hit during the atmospheric rivers that swamped much of southwestern B.C. in November 2021, washing away bridges and spurring landslides that killed five people.

But in neighbouring Washington state, the bulletin says high flows on the Nooksack River have reached "local flood stage.’’

It says "spillover’’ into the Sumas River watershed has been observed near the community of Everson, Wash., about 20 kilometres south of Abbotsford.

The centre says the spillover should be "short-lived’’ as upstream areas of the Nooksack have already reached peak levels and are now receding.

B.C. forecast centre issues flood warning for part of Lower Mainland amid...

[Flyron]

Pineapple Express: Massive Atmospheric River Set to Unleash Torrential Rain...

https://www.accuweather.com/en/winter-weather/monster-pacific-storm-to-firehose-california-with-rain-flooding-and-wind/1617049

[ghost7]

Summary:

• A deep area of low pressure approaching the northeast Pacific will drag a strong cold front across CA and NV for Wednesday into Thursday with a round of moderate to heavy precip.
• Heaviest amounts will fall along northern/central CA coastal locations, the Shasta Lake drainage, and portions of the Sierra with 2" to 5" local to 6" at the wettest locations.
• Another storm system will approach the CA coast for the upcoming weekend, however, with model differences confidence is currently lower with this incoming precip event.
• Significant rises are expected on Wednesday and Thursday across much of California.
• Rivers will be highest along the north coast and Sacramento River system. Many locations are expected to exceed monitor stage, with several expected to exceed flood stage.
• The Colusa Weir and Tisdale Weir are expected to flow again this week, with the possibility of Moulton Weir and Fremont Weir flow later in the week.

Confidence: Medium then Lower this Weekend

Staffing Level: Extended (24 Hours Starting Wednesday Morning)

Detailed Hydrometeorological Discussion: cnrfc.noaa.gov/discussion

Cresting on the orange and yellow gages will occur Wednesday afternoon through Thursday morning.

Projected 5-Day Rain Totals

[ghost7]

'kay. KSBY has a feature on debris flows and landslides in burn scars. A USGS Landslide Hazards Program team is working on the 2019 Cave Fire site. Soil saturation levels as covered in Hydrological Outlooks are another factor of risk. The language in the NWS issues is more specific about causes for pause.

Landslide hazard program gives insight into correlation between burn areas...

CA-LPF/SBC-Cave

State ID:CA 3 letter designator:LPF/SBC Fire name:Cave Location:highway 154/painted cave road Reported acres:3100 Rate of spread:rapid Report on Conditions:high winds Structure threat:yes Resources: Hazards: Weather: Radio channels: Scanner link:https://m.broadcastify.com/listen/feed/747 Webcam link:http://www.alertwildfire.org/centralcoast/index.html Agency Website:

CA-LPF/SBC-Cave??( Was Painted Cave)

New start near East Camino Cielo and Painted cave road. Column visible from Goleta/ downtwon Santa Barbara. SBC and LPF are sending a response