What did the sandstorm in the grasslands of southern Canada say?

Canada is the second largest country in the world, with an area of about100000 square kilometers, second only to the Russian Federation. Due to the bad climate in the north, only 65,438+02% of the land is suitable for agricultural development. Because of this, 30 million Canadians have to rely on the 300-kilometer narrow strip between the Atlantic Ocean and the Pacific Ocean on the southern border with the United States.

The Canadian Prairie is located on the northern edge of the Great Plains of North America, in a half circle from the Rocky Mountains to the Red River Basin, including the southern areas of Alberta, Saskatchewan and Manitoba, with a total area of about 65.438+096 billion hectares, accounting for 654.38+09.6% of the total land area.

Prairie area is Canada's grain package, settlement and development zone.

Developed agriculture covers an area of 37.7 million hectares, and grassland provinces account for 80% of Canada's agricultural base. Agriculture is the pillar industry here and the main wheat producing area in Canada. In fact, the three grassland provinces are one of the regions with the highest grain output in the world. Therefore, it won the reputation of "world granary".

18 18, within 50 years after the boundary between Canada and the United States was determined, Canada officially exercised sovereignty in 1867 according to the British North America Act. The federal government has promulgated many policies to encourage settlement and development of western grasslands, invested in the construction of the Canadian Pacific Railway, and implemented special transportation price concessions for settlers. Thousands of square kilometers of territory once considered worthless have been developed into settlements. However, until 188 1, the western plain was still uninhabited.

The temperature and precipitation in American desert in vast expanse are different, and the frequency of natural disasters such as sandstorm and drought is very high, especially in grassland areas.

/kloc-after the construction of settlement area began in the second half of the 9th century, it was built in 1860~ 1862, 1870~ 1873, 1886 ~ 1893. At the same time, various dry farming measures were accepted and adopted by some farmers, and early-maturing wheat varieties were cultivated. At the end of 19, the farming methods in dry land were improved, which triggered the second wave of immigrants to settle down and develop grassland areas.

The climate, vegetation and soil productivity of the whole region are constantly changing. Typical landforms include flat and broad plains and gently undulating plateaus, continuous hilly areas, canyons, mobile sand dunes, large reservoirs, lush wetlands, dense valley forests and exposed sandy bedrock.

Due to the barrier of the western Rocky Mountains, the grassland area is far from the ocean and is a grassland area with continental climate. It is extremely hot in summer and extremely cold in winter, with the highest temperature of 40℃ and the lowest temperature of -40℃. There is little precipitation, with an average annual precipitation of 250~750 mm, which belongs to arid and semi-arid areas. The annual precipitation in the red river basin of Manitoba province with high humidity is about 500 mm, and strong wind is also a unique weather in grassland areas. Strong winds dry up the soil and plants, especially in the south. There are no large water bodies in the upwind direction and prevailing wind direction, and droughts are frequent, and sandstorms often appear in the dry season.

Since 1880, the biggest change is to reclaim the Canadian prairie from the original natural grassland into an agricultural farming area. A large number of natural vegetation has been destroyed. In order to meet the population's demand for food and livestock feed, the original fertile topsoil was reclaimed as farmland to grow crops. At the beginning of the 20th century, due to human factors, the speed of reclamation in grassland areas was further accelerated. Many people question the practice of reclaiming the southern grassland to develop agriculture, because the early farmers didn't realize that they destroyed the grassland and caused soil erosion. However, Gray believes that as a country, Canada could not be where it is today without the settlement of grassland areas and agricultural development.

Arid areas are often affected by sandstorm activities, among which strong wind is an important factor of wind erosion. Wind erosion has been a long-term problem in western Canada since the beginning of agricultural reclamation. At the southernmost tip of the prairie, westerly winds prevail, including southwest winds and northwest winds. The prevailing wind carries the warm and humid air flow from the Pacific Ocean eastward through the mountains, and the air becomes cold, and the humid air flow drifts downward in the form of precipitation or snowfall. The more the airflow moves eastward, the more water falls in the form of snowfall. The mountain system here runs from north to south, without blocking the Arctic cold current from the north, and the cold winter permeates the whole grassland area. Similarly, there is no obstacle for the warm and dry air mass from the southwestern United States to push northward. So the atmosphere here is bumpy, the clouds are deep, there are strong winds everywhere, and the precipitation is soaring. Strong winds prevail in spring, and heavy rains pour down in summer, often accompanied by strong winds. At this time, the arid and loose surface and the field plots without vegetation cover are extremely vulnerable to wind erosion. At this time, sandstorms occurred rapidly, and black dust waves rolled up by strong winds could be seen thousands of meters away. Sandstorm is like a black wall, rolling and pressing to the ground. Locally called it God's "fainting".

Severe sandstorms are sometimes called sandstorms or "dust storms" because they sound more vivid. However, there is a big gap between the two. Sandstorms are often caused by strong winds that roll powdery substances on the ground into the air, and the height is higher, but sandstorms are different. Dust storm is a small atmospheric vortex, and the rolling dust cloud is mixed with dust or dust impurities visible to the naked eye. According to the frequency of long-term occurrence, sandstorms occur strictly about five times a year in some parts of Saskatchewan province, but the strong wind accompanying sandstorms affects a wider area.

Desert-like landscapes can be seen everywhere in grassland areas. For example, in the Red Deer River Basin in Alberta, excessive water erosion and wind erosion have carved various grotesque shapes on the local sandstone, which is called "ominous things" locally, and soil erosion has also caused mobile sand dunes. The land in southeastern Alberta and southwestern Saskatchewan is extremely vulnerable to wind erosion. Although there is no clear information, during the "black storm" in the 1930s, the whole topsoil was swept away by strong winds, resulting in the loss of 2000 tons of topsoil per hectare, which led to the erosion of nearly 20% of the fertile fields in the grassland areas during the black storm.

Up to now, the most disastrous sandstorm and drought occurred in the "evil dust of the 1930s" in the 20th century, which made three provinces in grassland areas suffer greatly. From 1933 to 1937, the precipitation in this area almost decreased by 1/2. Results The output of wheat and corn decreased by 32%~50% respectively, 200,000 farms went bankrupt, 300,000 people moved to other places, and 50,000 farmers relied on government relief. In the Palisade Delta alone, 654.38+10,000 families were forced to give up farming, and men took simple bags on their shoulders and took railway wagons, far away from grassland areas. 1 931August1day, the Canadian Red Cross launched a campaign to donate food and clothing to125,000 poor farmers who suffered from hunger and cold for three consecutive years, which aroused national concern about the seriousness of sandstorms and drought disasters.

Throughout the 1930s, wind erosion and drought were extremely serious. During this period, 250 cities and more than 7 million hectares of land in grassland areas were affected by drought. There is no accurate record of how much farmland was destroyed by wind erosion. At that time, it was no exaggeration to use "out of control" to describe the state in which the top soil of the land was eroded. Ge Lei said that building fences and leaving weeds are effective measures to maintain soil and sand. This measure is absolutely necessary, because in just one year, the barbed wire was completely buried by the sandy material carried by the sandstorm. The drought in the 1930s also brought the plague of locusts. In the first year of the occurrence of locust plague in Alberta, the seriously affected area was about 4 100 square kilometers, and by 1939, the area affected by locust plague reached 155000 square kilometers. The moderately affected area of Saatchi Bay has increased from 4,000 square kilometers in 193 1 to more than 260,000 square kilometers, accounting for more than 40% of the province's area.

Living on the grassland is a life-and-death struggle. Farmers have lost the fruits of their labor, and there is almost no grain harvest everywhere. Sandstorms and droughts have destroyed towns and farmers' fields, causing incalculable losses to people's property and food production.

Historians recorded the long-term harm of local residents to sandstorms. "Farmers are often blinded by sandstorms and grope their way out of the fields to go home." Momativuko and Eastcott describe it this way: "People wrap their heads in shirts or retract their heads into coats to prevent dust from entering their noses." Older local residents still remember the "evil dust" in the 1930s, when people really experienced a terrible disaster. All kinds of imaginable disasters have happened, such as sandstorm, ruthless drought, blazing high temperature and so on. What's more, "people have to buckle the dishes on the table, otherwise the tableware is full of sand and dust and they can't eat."

Gray used the following vivid words to describe the sandstorm that occurred on the Canadian prairie in the 1930s: "The wind rolled up the topsoil and filled the railways in Alberta like heavy snow, and the sandstorm eroded, transported and accumulated the topsoil on the barren land in Saskatchewan to the fertile land. Regina, Muscho and Swift Cullen are covered with a thick layer of dust inside and outside. Winnipeg's golden coat was baptized by dust. Snowfall in winter makes roads impassable, and monsoon sandstorm in summer paralyzes roads. Sandstorms buried residents' courtyard walls and fences, blocked windbreaks and buried vegetable gardens, orchards and gardens. Sand overflows the henhouse and tears the windows, so that every room is full of dust and sand, and yellow sand accumulates in front of the door, making people unable to go out, leave the village and walk. It can be said that it is difficult to get out of the house because of sandstorm, and a sandstorm destroyed the home. "