Map of Lac des Trois Milles with depth contours

Lac des Trois Milles

45.6889° N, 70.9201° W

Depth contours from the 1966 government survey. Not for navigation.

Download the depth map (SVG)

Lac des Trois Milles is 3 m deep at its deepest point, shallower than 97% of the 1,506 surveyed lakes in Quebec. It covers 1.01 km² and lies 1.7 km south of Saint-Samuel-Station.

Maximum depth
3 msurveyed 1966
shallower than 97% of the 1,506 surveyed lakes in Quebec
Area
1.01 km²
larger than 74% of the 29,407 lakes in Quebec
Shoreline
5.5 km
longer than 64% of the 29,407 lakes in Quebec
Water clarity
2.5 mSecchi depth, 2025
less clear than 78% of the 805 monitored lakes in Quebec
Elevation
477 m

Today on the water

YELLOW ADVISORY - FROST · issued 8:47 a.m. EDT
Temperatures will drop to near freezing overnight tonoght as well as overnight Saturday to Sunday.

Take preventative measures to protect cold-sensitive plants, trees, and crops.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to QCstorm@ec.gc.ca or post reports on social media using #QCStorm.

Official alert on weather.gc.ca · expires 12:47 a.m. EDT Saturday

6.2 °C

Wind WNW 11 km/h

Observed at Lac-Mégantic, as of 9:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 10 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Hourly forecast, next 24 hours
Time10 a.m.1 p.m.4 p.m.7 p.m.10 p.m.1 a.m.4 a.m.7 a.m.
Wind km/hW 20W 20W 20W 20W 15W 10W 10W 15
Gusts km/h404040
Waves (est.) m0.20.20.20.2
Temp. °C9111186420
Precip. %404040400000

Today: Mainly cloudy with 40 percent chance of showers. Risk of a thunderstorm late this afternoon. Wind becoming west 20 km/h gusting to 40 this morning. High 12. UV index 3 or moderate.

Weather: Lac-Mégantic (local forecast), as of 9:05 a.m. EDT

Sun and moon

Civil dawn
6:22 a.m.
Sunrise
6:52 a.m.
Sunset
6:08 p.m.
Civil dusk
6:38 p.m.
Moonrise
5:42 a.m.
Moonset
5:26 p.m.
Moon
Waning crescent, 1% lit

Data Source: Environment and Climate Change Canada. Local times.

How waves are estimated

Significant wave height from the forecast hourly wind and the open-water distance (fetch) upwind, using the SMB method (US Army Corps of Engineers Shore Protection Manual, 1984), rounded up to the next 0.1 m. It is not a measurement: gusts, leftover swell and shoals can make water rougher. Under 0.2 m: calm; 0.2–0.5 m: choppy; over 0.5 m: rough.

Depth

How to read it: the lake’s area is sorted from the shore to the deepest point. Where the curve is flat, large areas share one depth (flats and weed beds); where it drops, depth changes quickly (drop-offs).

The government depth survey from 1966 records a maximum depth of 3 m, drawn from 3 depth contours.

Not for navigation. Depths are from government surveys and may be outdated.

Water

Trophic status from the latest monitoring: meso-eutrophic (transition).

Clarity was measured with a Secchi disk in 15 years between 2006 and 2025; the latest annual mean is 2.5 m.

Water clarity (Secchi depth, m)
Total phosphorus (µg/L)