How Clean Is Thunder Lake?
Thunder Lake is among the cleanest lakes in Minnesota. Its nutrient and algae readings come from EPA monitoring data. Water clarity (Secchi depth): 16.5 ft. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Trophic State Index: 38.
Cleanliness Snapshot
| Metric | Thunder Lake | Minnesota avg |
|---|---|---|
| Water Clarity (Secchi) | 16.5 ft | — |
| Phosphorus | 10 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 2.4 µg/L | <10 = clean |
| Trophic State Index | 38 | <50 = clean |
How does Thunder Lake compare?
Thunder Lake's readings match or beat the Minnesota state average. It ranks #37 of 104 lakes in Cass County on nutrient and algae readings. Multi-year monitoring data shows water quality is improving based on 6 years of records.
Stays via Stay22
Where to stay near Thunder Lake
Compare cabins, hotels, and vacation rentals near Thunder Lake in Cass County, Minnesota. Live availability and prices for your nights. Switch the map to Satellite to see how close each stay is to the water.
Top-rated places to stay near Thunder Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Thunder Lake?
Get lake water-quality updates plus the best cabin & lodging deals near Thunder Lake — straight to your inbox. No spam, unsubscribe anytime.
Watch Thunder Lake water quality
Get an email when the clarity or algae readings change. Unsubscribe anytime.