California
Toxic algae in Alpine County lakes
19 lakes and waterways in Alpine County have harmful algal bloom reports in California's official data. The most recent entry is for Arnot Creek: There are no bloom reports for Arnot Creek in the last 30 days of California's data. The most recent was a bloom report on 9 September 2026 at (534SED001). Arnot Creek, Red Lake Creek and Red Lake and 2 more have had blooms in three or more years.
Lakes with bloom history
Newest report first. Each lake has its own page with the full history and what the results mean.
Other waterbodies with a report
These have one or two reports in a single year, which isn't enough history for a page of their own yet.
- Bryant Creek 2023
- Elbow Creek 2025
- Forestdale Creek 2023
- Hot Springs Creek 2024
- Indian Creek 2023
- Leviathan Creek 2023
- Pacific Creek 2025
- Red Lake Tributary 2022
- Spratt Creek 2025
- Stevens Lake 2019
- Summit Lake 2020
- Tamarack Lake 2021
Source: California State Water Resources Control Board, official data, checked 24 October 2026. For today's conditions see the California HABs Portal map. No report doesn't mean a lake is safe: most water is only tested occasionally.