Is Slate Creek safe? Toxic algae status
Sierra County, California. Harmful algal bloom (blue-green algae) reports from the California State Water Resources Control Board.
Data checked 24 October 2026. California data is updated daily.
3
bloom reports since 2021
2 of 6
years with a bloom reported (2021–2026)
1
advisories recommended: 1 Caution, 0 Warning, 0 Danger
Year by year
Each box shows bloom reports logged that year, coloured by the highest advisory recommended.
Reports at Slate Creek are most often logged in June, July and August.
Recent reports
| Date | Location | Result |
|---|---|---|
| 8 July 2026 | (USFS) (517SLT050) | Bloom reported |
| 5 August 2021 | ~0.7mi below Buckeye Cr. | Caution |
| 14 June 2021 | Slate Creek (USFS) | Bloom reported |
What the results mean
Algae may be present. Stay away from scum and discoloured water, and keep pets and livestock from drinking it.
Toxins at higher levels. No swimming, and keep pets and children well away from the water.
High toxin levels. Stay out of the water and off the shoreline.
Dogs and toxic algae
Dogs face the greatest risk because they swallow water and lick algae off their fur. If a bloom has been reported, keep dogs out of the water and away from scum on the shore. If your dog swims in water that might have algae, rinse it with clean water straight away and call a vet if it seems unwell.
Common questions
Is Slate Creek safe to swim in?
The most recent entry in California's published data is from 8 July 2026: bloom reported ((USFS) (517SLT050)). Blooms have been recorded at Slate Creek in 2 different years, so treat green, scummy or discoloured water with caution. For current conditions, check the California HABs Portal map and posted signs.
When does Slate Creek get algae blooms?
In the state's records, reports are most often logged in June, July and August. Blooms are most likely in warm, calm weather, but they can appear at other times of year.
Source: California State Water Resources Control Board, official data. Slate Creek spans Sierra County and Yuba County; reports from all of them are combined here. This page is independent and not affiliated with the State of California.