A snow blower, also known as a snow thrower is a machine for removing snow from an area where it is not wanted, such as a sidewalk, driveway, or any other snow laden path. Modern snow blowers use either electric power or a gasoline or diesel engine to throw snow to another location or into a vehicle to be hauled away. This is in contrast with the action of snow plows, which push snow to the front or side (shovels can be similarly used).
Snow blower can range from the very small, capable of removing only several inches (a few cm) of light snow in a 18 to 20 inch (45 to 50 cm) path, to very large, capable of moving 10 foot (3 m) wide swaths of heavy snow up to 6 feet (2 m) deep. Snow blowers can generally be divided into two classes: single stage and two stage.
Single stage snow blowers
Single stage snow throwers use a single high-speed impeller to both move the snow into the machine and force it out the discharge chute. The impeller is commonly in the form of two or more curved plastic paddles that move snow towards the centerline of the machine where the discharge chute is located. Single stage snow throwers usually are light duty machines. Small electric machines can actually be picked up to chew away deep snow banks a layer at a time.
One exception to the rule are the enormous single stage rotary snow throwers used by railroads to clear tracks in mountainous areas. These rotary snowplows use a single large impeller that can span the entire width of the train and typically discharge to the side.
Two stage snow blower
By comparison, two stage snow blowers have one or more low-speed metal augers that break up the snow and move it into a separate high-speed impeller (sometimes called the fan). The impeller 'blows' the snow out the discharge chute with considerable force. All but the lightest-duty snow throwers are typically two-stage machines.
Two stage snow blowers range in power from a few horsepower to very large machines powered by diesel engines of over 1000 horsepower (750 kW). The large machines are used for clearing roadways and airport runways. These are capable of removing large amounts of snow quickly. Some municipalities use larger snowblowers to clear snow from streets after a snowfall, blowing the snow into trucks which haul it away.
Two stage snow blowers for home use are often self-propelled, having either large wheels equipped with tire chains or, in some cases, tracks. These are usually single-purpose snow blowers, though some are detachable front ends that can be replaced with other implements, such as a garden tiller.
When choosing a snow blower one must decide whether the area is large or small or if in fact you'll be using your snow blower frequently or rarely, depending on the region you live in.