The Great Lakes and St. Lawrence Lowlands

by Ladursa Sivakumar

Physical Features


The St. Lawrence Lowlands has a continental climate because this region is not located near any oceans and the average annual climate is above 25oC and receives less than 1000mm of precipitation. The climate in this region is affected by latitude since the area is somewhat near the equator, the St. Lawrence lowlands doesn’t have extremely cold winters but does have hot summers. However, the city of Toronto has a moderating effect because of nearness to the Great Lakes. The St. Lawrence lowlands climate is also affected by winds and air masses because of the jet stream which occurs when a hot front and cold front collide and so this brings a cool breeze to this region. The jet stream also causes this region to receive cyclonic precipitation because of the collision of the cold and warm fronts, but the region also receives convectional precipitation in the summer because of the warm temperatures. The St. Lawrence region receives lots of sunlight and has humid air, and the humid air rises out, precipitation occurs.


Continental glaciers have transformed and shaped the St. Lawrence Lowlands landscape into what it currently looks like now. In the past, there have been numerous amounts of glaciations; however, the last one which was approximately 18,000 years ago covered the entire St. Lawrence region with 2 enormous ice sheets. The land was pushed downwards because of these ice sheets and  caused the mountain and rocky land to erode into flat lowlands with rolling hills. The last glaciations also deposited till which created one of Canada’s famous tourist attractions, Niagara Falls. This region was also shaped through the process of two tectonic plates moving apart from each other which is called Divergent. This created a valley in between which we now know as the St. Lawrence River.


In the St. Lawrence Lowlands, the soil is very rich & fertile and perfect for growing crops. This is because the St. Lawrence Lowlands was once flooded by the sea for a long period of time and organisms & plants left many layers of sediments behind after falling into the sea. Furthermore, plants have a lot of time to grow since in this region, the growing season is long. The plants will eventually die, and when they decompose, they help add a natural organic layer on the topsoil level. There is a variety of vegetation in this region because this region provides a great growing environment for plants and crops.


During the Paleozoic era, many sedimentary rocks were created and these sediments were compressed for over millions of years. Therefore, the St. Lawrence region mainly consists of sedimentary rocks and minerals which are within rocks. Some examples of minerals include iron, copper and zinc. Also, it is likely that there were metamorphic rocks are the erratic rocks from the Canadian Shield deposited in this region by glaciers.

Business Activities

The St. Lawrence region has some of the largest industries because of the natural resources there such as minerals, soil, forestry and water. Manufacturing is one of the largest industries in the region because the landforms and physical features are good sources for materials required for producing goods. Usually, the factories in this region are built near:

  • water (transportation purposes and hydro-electricity to run the factories)
  • where an abundance of minerals can be found
  • close to people (more employees for the factory)

In addition, the agriculture/farming industry is also a large industry in this region because this area meets all the requirements for crops and plants to be grown well. This region has rich nutritious calcified soil, moderate climate, not too much precipitation and flat lands and rolling hills, which is perfect for agriculture. Many people in this region grow crops, fruits and vegetables to sell them to factories and this their way of earning money and making a living.

Furthermore, the forestry industry is also a well known industry in the St. Lawrence region because there is lots of vegetation in this region and it consists of coniferous, deciduous and mixed trees. The trees in this region contribute to our daily lives because the trees are turned into things that many people use on a daily basis. For example, newsprint, paper products, pulp, lumber, etc.

Influence of climate change

A changing climate in the St. Lawrence region can create an impact on the region depending on the types of new climate the region will face. Too much precipitation can cause flooding of the Great Lakes, and more precipitation in the winter seasons on the soil can cause erosion in the region. Flooding can also cause disruption for crops and plants, and may have an impact on the agriculture industry as the production of food and medicines would be weak and unavailable. Climate change will also have in-lake effects because there will be a change in temperature in the lakes, creating a change in fish's natural habitats. Moreover, forests cover large areas in the St. Lawrence Lowlands, and they provide suitable living environments for animals and provide great recreational opportunities like camping, hiking, fishing, etc and also provide necessities for humans through the forestry industry. However, with a change in climate a lot can change such as the amount of production made from forests and as a result, forestry industry possibly may not be a large good industry anymore for the St. Lawrence region. 

Risk of natural disaster

In the St. Lawrence region, there are risks of natural disasters such as earthquakes, floods, forest fires and landslides to occur.


  • When stress is built up within the region’s geological attributes, a sudden movement of the earth’s crust occurs, and this is called an earthquake
  • Earthquakes can occur suddenly and without a warning
  • Depending on the size and harshness of the earthquakes, they can cause very small or no damage to being extremely destructive and dangerous


  • When there is constant rain that occurs for many hours for days, there can be excess water that even causes overflows in sewers, this can be described as a flood
  • Floods can be very destructive and cause major damage to houses, properties, vehicles
  • Flooding can kill animals and their natural habitats and can cause a disruption to the ecosystem because the water becomes contaminated with all sorts of waste

Forest fires

  • 45% of forest fires occur because of lighting
  • The sap inside of trees are conductors and lighting strikes on things that can conduct electricity, and with large forests in the St. Lawrence, forest fires can occur easily
  • Forest fires can cause severe damage as they can destroy wildlife habitats and animals within the forest areas
  • The forests can cause a disruption in the forestry industry since the trees are natural resources needed in order for this industry to function and run
  • The Forest fires also release greenhouse gases into the atmosphere which can eventually cause climate change


-A landslide is when rocks or loose sediments move downwards

-Landslides rarely occur, and when they do, the speed of the landslide can be anywhere from extremely slow to extremely fast

-Landslides are caused by human actions or can just occur because of nature

Lac des Seize, Montreal (April 2014|)

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