Map of Lac Lanthier with depth contours

Lac Lanthier

46.4627° N, 74.8378° W

Depth contours from the 2013 government survey. Not for navigation.

Download the depth map (SVG)

Lac Lanthier is 15 m deep at its deepest point, shallower than 56% of the 1,506 surveyed lakes in Quebec. It covers 1.23 km² and lies beside Lac-Lanthier-Est.

Maximum depth
15 msurveyed 2013
shallower than 56% of the 1,506 surveyed lakes in Quebec
Area
1.23 km²
larger than 77% of the 29,407 lakes in Quebec
Shoreline
12.7 km
longer than 82% of the 29,407 lakes in Quebec
Water clarity
2.7 mSecchi depth, 2025
less clear than 74% of the 805 monitored lakes in Quebec
Elevation
259 m

Today on the water

3.2 °C

Wind calm

Observed at Mont-Tremblant, as of 5:00 a.m. EDT

calm Estimated waves, next 12 hours: up to 0.1 m. Around 6 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Hourly forecast, next 24 hours
Time6 a.m.9 a.m.12 p.m.3 p.m.6 p.m.9 p.m.12 a.m.3 a.m.
Wind km/hW 10W 10W 20W 20W 10W 10NW 10NW 10
Waves (est.) m0.10.10.10.10.1
Temp. °C58997410
Precip. %404040400000

Today: A mix of sun and cloud with 40 percent chance of showers. Wind becoming west 20 km/h near noon. High 9. UV index 3 or moderate.

Weather: Mont-Tremblant (local forecast), as of 5:03 a.m. EDT

Sun and moon

Civil dawn
6:38 a.m.
Sunrise
7:08 a.m.
Sunset
6:23 p.m.
Civil dusk
6:53 p.m.
Moonrise
5:59 a.m.
Moonset
5:41 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

38% of Lac Lanthier is shallower than 3 m, and 44% is deeper than 5 m.

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 2013 records a maximum depth of 15 m, drawn from 50 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 Depths are from government surveys and may be outdated.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 17 years between 2008 and 2025; the latest annual mean is 2.7 m.

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