Active AlertsTrinidad, CA

What: Flooding caused by excessive rainfall is possible.
Where: A portion of northwest California, including the following areas, Mendocino Coast, Northeastern Mendocino Interior, Northern Humboldt Coast, Northern Humboldt Interior, Northern Lake, Northwestern Mendocino Interior, Southeastern Mendocino Interior, Southern Humboldt Interior, Southern Lake, Southern Trinity, Southwestern Humboldt and Southwestern Mendocino Interior.
When: From Friday afternoon through Sunday evening. Additional heavy rainfall will be possible Sunday through early next week.
Impacts: There will be an increased risk of rock and land slides along roadways. 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. Storm drains and ditches may become clogged with debris.
Additional Details: - Widespread moderate to heavy rain from two consecutive strong weather systems will produce 2-4 inches of rainfall Friday afternoon through late Sunday. - http://www.weather.gov/safety/flood

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.

What: For the Coastal Flood Warning, High astronomical tides and large surf will cause moderate flooding in low lying areas around Humboldt Bay Coast. Up to one foot of saltwater inundation above ground level is possible in low lying areas near shorelines and tidal waterways. Between 9.3 and 9. 6 feet MLLW at the north spit tide gauge is predicted. For the Coastal Flood Watch, High astronomical tides may cause moderate to locally major flooding in low lying areas along the Redwood and Mendocino Coast. Up to 1.5 foot of saltwater inundation above ground level is possible in low lying areas near shorelines and tidal waterways. Tides may exceed the highest astronomical tide on record at the North Spit tide gauge during the morning high tides on Friday and Saturday.
Where: Northern Humboldt Coast County.
When: For the Coastal Flood Warning, from 7 AM to 11 AM PST Thursday. For the Coastal Flood Watch, from Thursday morning through Saturday afternoon. High tide is at 8:08 am at the Humboldt Bay North Spit tide gauge. Saltwater inundation will be possible 1 to 2 hours before and after high tide.
Impacts: Several coastal roads may be closed. Low lying property and some critical infrastructure will be inundated. These impacts will include, but not limited to, roadways in King Salmon and the Arcata bottoms. Shoreline erosion will occur.

A Coastal Flood Warning means that flooding is occurring or imminent. Coastal residents in the warned area should be alert for rising water and take appropriate action to protect life and property. Feet Above Ground is locally defined as feet above the Highest Astronomical Tide or HAT.

What: South winds 15 to 25 mph with gusts up to 45 mph expected.
Where: Del Norte and Northern Humboldt Coast, and Mendocino Coast.
When: From 1 PM Friday to 10 PM PST Saturday.
Impacts: Wind gusts will be particularly strong along windward ridges and exposed coastal headlands.

Winds this strong can make driving difficult, especially for high profile vehicles. Use extra caution.

A series of atmospheric rivers will bring an increased risk for urban and small stream flooding late this week and into this weekend. The first round of rain will arrive Wednesday night into Thursday and provide generally light to moderate rainfall amounts. Locally heavy rain is expected in the King Range. This initial period of rain will set the stage for a more intense rainstorm expected to arrive Friday into Friday night. Current indications are for the heaviest rainfall to occur during the day on Friday into Friday night. The greatest risk for small stream flooding will occur during this time period and probably continue into Saturday after heavy rain has ended due to the lag in rainfall run-off. Road closures will be possible. At this point, the area of greatest concern is in southern Humboldt and northwest Mendocino counties. Small rivers, streams and creeks such as Elk river, Jacoby creek and Mattole river could exceed their banks and flood area roads. Southern Mendocino and Lake counties may also experience heavy rain and road flooding will be possible. Mainstem rivers will also likely rise sharply and will need to be monitored for possible flood stage exceedance. Be on the lookout for watches, advisories and warning as this next heavy rain event unfolds. Plan to avoid driving through areas that tend to flood.