Map of Lac de la Montagne with depth contours

Lac de la Montagne

45.9908° N, 74.3185° W

Depth contours from the 2010 government survey. Not for navigation.

Download the depth map (SVG)

Lac de la Montagne is 17.6 m deep at its deepest point, deeper than 54% of the 1,506 surveyed lakes in Quebec. It covers 0.38 km² and lies 1 km southeast of Domaine-des-Lacs-Boisés.

Maximum depth
17.6 msurveyed 2010
deeper than 54% of the 1,506 surveyed lakes in Quebec
Area
0.38 km²
larger than 55% of the 29,407 lakes in Quebec
Shoreline
5.5 km
longer than 64% of the 29,407 lakes in Quebec
Water clarity
7.4 mSecchi depth, 2025
clearer than 94% of the 805 monitored lakes in Quebec
Elevation
408 m

Today on the water

2.4 °C

Wind calm

Observed at Sainte-Agathe, as of 8:00 a.m. EDT

calm Estimated waves, next 12 hours: up to 0.1 m. Around 9 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Hourly forecast, next 24 hours
Time9 a.m.12 p.m.3 p.m.6 p.m.9 p.m.12 a.m.3 a.m.6 a.m.
Wind km/hW 10W 20W 20W 10W 10NW 10NW 10var. 5
Waves (est.) m0.10.10.10.1
Temp. °C8997410-1
Precip. %40404000000

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: Sainte-Agathe (local forecast), as of 8:03 a.m. EDT

Sun and moon

Civil dawn
6:36 a.m.
Sunrise
7:06 a.m.
Sunset
6:22 p.m.
Civil dusk
6:51 p.m.
Moonrise
5:57 a.m.
Moonset
5:40 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

15% of Lac de la Montagne is deeper than 10 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 2010 records a maximum depth of 17.6 m, drawn from 29 depth contours.

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 Depths are from government surveys and may be outdated.

Water

Trophic status from the latest monitoring: oligotrophic.

Clarity was measured with a Secchi disk in 15 years between 2008 and 2025; the latest annual mean is 7.4 m.

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