Lakes of this area range in size from many square kilometres in area (Eagle (L469), Dryberry (L466)) to tiny ponds of a hectare or so. However, the majority of lakes are between 5 and 50 hectares in surface area. The rugged topography has produced many lakes that are deep relative to their surface areas, meaning that they thermally stratify in summer. In addition, many are relatively protected from wind because of steep shorelines and surrounding forests. Shorelines often consist of exposed bedrock interspersed with sections of sand, gravel and cobbles. The profundal sediments usually consist of soft organic material, colourfully referred to as "loonshit".
These lakes usually remain ice-free from 6 to 7 months each year. Midsummer epilimnetic temperatures will typically reach between 20 and 25 degrees Celcius, although some large, deep lakes sometimes may be cooler and some shallow lakes warmer. Ice cover typically reaches a depth of from 0.5 to 1 metre, depending on the severity of the winter and the amount of snow cover. Snow cover is normally deeper on the small sheltered lakes where it is less affected by wind action. Particularly during periods of high snowfall, the formation of "slush" layers under the snow is common as the weight of snow forces the ice down and liquid water rises through cracks to saturate the lower strata of snow.
Most of these lakes are dimictic or monomictic, depending on their size and exposure to surface winds. Complete mixing is more typical in fall rather than spring, particularly for the small, deep, sheltered lakes. Occasionally, some of these lakes may not mix completely for several years, and one of the designated research lakes (111) is clearly meromictic. Three other lakes in the ELA (120, 241, 615) are known to be meromictic.