BorealBoundFrançais
Map of Lac de l'Est with depth contours

Lac de l'Est

45.9455° N, 71.4198° W

Depth contours from the 2012 government survey. Not for navigation.

Download the depth map (SVG)

Lac de l'Est, Quebec. 45.9455° N, 71.4198° W

Maximum depth 18.4 m (2012 survey). Scale bar on the map.

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 Depths are from government surveys and may be outdated.

borealbound.ca/lakes/qc/lac-de-l-est-near-thetford-mines/, compiled October 9, 2026

  • Canadian Geographical Names Database, Natural Resources Canada. Contains information licensed under the Open Government Licence – Canada.
  • HydroLAKES v1.0, Messager et al. 2016 / WWF HydroSHEDS. Licensed under CC BY 4.0.
  • Census boundaries and population, 2021, Statistics Canada. Adapted from Statistics Canada. This does not constitute an endorsement by Statistics Canada.
  • Géobase des bathymétries de lac du Québec (GBLQ), Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs. Licensed under CC BY 4.0. Source: Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP), Données Québec.
  • États trophiques des lacs (RSVL), Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs. Licensed under CC BY 4.0. Source: Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP), Données Québec.
  • City page weather forecasts and alerts, Environment and Climate Change Canada. Contains data from Environment and Climate Change Canada (ECCC Data Servers End-use Licence).

Lac de l'Est is 18.4 m deep at its deepest point, deeper than 55% of the 1,506 surveyed lakes in Quebec. It covers 0.77 km² and lies 3.4 km southwest of Coleraine.

Maximum depth
18.4 msurveyed 2012
deeper than 55% of the 1,506 surveyed lakes in Quebec
Area
0.77 km²
larger than 70% of the 29,407 lakes in Quebec
Shoreline
5.5 km
longer than 64% of the 29,407 lakes in Quebec
Water clarity
2.8 mSecchi depth, 2024
less clear than 71% of the 805 monitored lakes in Quebec
Elevation
310 m

Today on the water

YELLOW ADVISORY - FROST · issued 4:39 a.m. EDT
Temperatures will drop to near the freezing mark overnight tonight.

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 8:39 p.m. EDT

5.4 °C

Wind SW 7 km/h

Observed at Thetford Mines, as of 6:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 9 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Time7 a.m.10 a.m.1 p.m.4 p.m.7 p.m.10 p.m.1 a.m.4 a.m.
Wind km/hW 10W 20W 20W 20W 20W 15W 10W 10
Gusts km/h404040
Waves (est.) m0.10.20.20.2
Temp. °C7911118642
Precip. %4040404040000

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: Thetford Mines (local forecast), as of 6:01 a.m. EDT

Sun and moon

Civil dawn
6:24 a.m.
Sunrise
6:54 a.m.
Sunset
6:10 p.m.
Civil dusk
6:40 p.m.
Moonrise
5:44 a.m.
Moonset
5:28 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

27% of Lac de l'Est is shallower than 3 m, and 20% 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 2012 records a maximum depth of 18.4 m, drawn from 13 depth contours.

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

Water

Trophic status from the latest monitoring: mesotrophic.

Clarity was measured with a Secchi disk in 4 years between 2008 and 2024; the latest annual mean is 2.8 m.

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