People may not give much consideration to freezing temperatures, but the consequences can be disastrous. During the historic winter outbreak in Texas in February 2021, extremely cold temperatures along with snow, sleet, and freezing rain impacted the entire state. Many records were shattered during this unprecedented “Valentines” storm system. In College Station, Texas, the coldest temperature was 5 degrees Fahrenheit at 7:26 on February 16, 2021. The coldest windchill was −8 degrees Fahrenheit at 8:53 on February 15, 2021. The longest stretch of freezing temperatures was 86 consecutive hours from 3:53 pm on February 13, 2021 to 5:53 am on February 17, 2021. As a result, many water pipes froze, and this damaged many buildings and produced significant property losses.
One of the most‐damaging and disruptive ice storms was experienced along the U.S.–Canadian border in January 1998. Ice piled up several times higher than prior records, and many power lines and transmission towers collapsed due to the excessive weight of thick ice. Widespread blackouts occurred in this region. A similar event occurred in Texas in February 2021. The combination of ice and extremely cold temperatures impacted the state for multiple days. The power grid was damaged and disrupted, and as many as 4 million people were without electricity over an extended period of time. Water mains in the street and water lines in homes broke across the state, and people were left without drinking water. Grocery stores also ran out of food and supplies, and deaths were reported due to hypothermia. Both of these storms reveal just how vulnerable infrastructure can be to the forces of nature.
Fog and dust storms are other hazards that result from atmospheric conditions. Fog occurs near the ground when water vapor condenses as warm and cold air interact. In 2017, dense fog accumulated between the cities of Hanford and Lemoore in California. Visibility became problematic and a series of accidents along Highway 198 involved more than 50 vehicles.
Dust storms (also known as sandstorms) occur in arid and semi‐arid locations such as the Sedan in Africa. They are also common in states like Arizona—particularly in April. Known as “haboobs,” these events make visibility problematic and likewise create many traffic accidents. Haboobs can also create respiratory problems since the fine dust will inevitably end up in people’s lungs.
A final atmospheric hazard to be discussed here is a heat wave. A heat wave is a prolonged period of high temperatures that may also be coupled with excessive humidity. Heat waves create loss of agricultural crops and also stress humans to the point that they cannot cool their bodies through the normal process of sweating. If relief from the weather or medical care is not given, coma, paralysis and death will follow. For instance, around 700 deaths (mainly among the elderly) resulted from a prolonged heat wave in Chicago in July 1995. The danger of such events requires constant communication with the public to alert them of such dangers. One of the things that needs to be relayed to the public is the heat index, which describes the severity of the situation. This index incorporates both temperature and humidity into a scale. It is used by meteorologists to help warn people to stay inside and drink lots of water.
For Example
Heat Wave in France
In August 2003, France experienced some of the highest minimum and maximum daily temperatures recorded in history. Because several families and physicians had taken time off from work during this typical vacation period, many elderly individuals were left at home or without sufficient care in hospitals and nursing facilities. The lack of air‐conditioning units in France combined with temperatures up to 104 degrees Fahrenheit and insufficient fluid intake resulted in the death of as many as 15,000 people. Heat waves such as this one are not always recognized as significant hazards, but their impact can be extensive as France discovered.
1.2.3 Hydrologic Hazards
Hydrologic hazards are closely related to atmospheric hazards and these agents have a specific impact on the earth’s water systems. There are several types of hydrologic hazards, one of them being floods. Floods are the most prevalent of any hazard around the world and in the United States—whether natural or otherwise. They are also among the costliest. Episodes of flooding occur when there is too much precipitation or where
there is an inability for soil to absorb water that has fallen to the ground. Flooding can also result from melting snowpack and ice jams. Soil type, topography, deforestation and level of development all have bearing on flooding. For instance, clay soils are more likely to produce runoff in comparison to sandy soils. Hills, valleys, and the use of cement or asphalt on streets and parking lots in highly urbanized areas may also contribute to this type of hazard.
The 1993 great Midwestern flood is the most widespread and costly flood in U.S. history. Months of unusually wet weather and the seasonal snowmelt overwhelmed the Mississippi River Basin with water. Dykes, locks, and dams were eventually filled to capacity, and many of them were breached. The water emitted from broken levees only added to the flooding downstream. Thousands of people had to be evacuated and property losses totaled in the billions of dollars.
For Example
Other Causes of Flooding
Dams and dam failures can also lead to flooding. One of the most‐deadly events occurred in Italy. In 1960, the Vajont Dam was constructed, and it was one of the tallest dams in the world. Unfortunately, when the dam was filled up this caused the neighboring mountainside to become water‐logged. Although the dam was drained 1/3 the capacity, a massive mudslide created a wave that overtopped the dam. 50 million cubic meters of water rushed down into the Piave Valley below, and 1,900–2,500 people lost their lives in this disaster.
In the United States, a flash flood occurred in Idaho on June 5, 1976. The Teton Dam suffered a catastrophic failure. The rushing water killed 11 people and over 13,000 cattle. In 2017, the Oroville Dam in California almost collapsed and forced the evacuation of nearly 200,000 people. The repairs cost over $1 billion. Sadly, many of the dams in the United States are aging and even reaching the end of their lifespan. In fact, in a recent assessment, 91,000 dams in the United States received a D‐letter grade. There is concern that more episodes of flooding will result.
Storm surges and coastal erosion may result from hurricanes or other types of phenomena in the hydrosphere (e.g., low‐pressure systems, strong winds, high tides, etc.). A storm surge is a temporary rise in the water level of an ocean or river estuary. Flooding is a product of storm surges, and it can take days and weeks for water to recede after such events. Coastal erosion may also occur as a result of storm surges, and it often damages roads, bridges, dunes and beaches. Louisiana and Florida are frequently affected by storm surges and coastal erosion associated with hurricanes. Losses can amount to millions of dollars.
Droughts are another kind of hazard related to the hydrologic system. Low amounts of rainfall and high evaporation rates due to warm or hot temperatures lead to conditions of drought. Dust storms, desertification, and salinization of soil also result from droughts. Drought can have a negative impact on agricultural output. The Great Depression was triggered, in part, by severe drought. However, droughts do not typically result in a substantial shortage of the overall food supply in the United States (although the provision of individual crops may be extremely low). In contrast, famines in other countries can be especially deadly. The lack of adequate food intake has resulted in malnourishment and the spread of fatal diseases in Ethiopia in the 1980s and Niger in the mid‐2000s.
For Example
The Sahel Drought and Famine
From 1961 to 1990, several countries in the Sahel region of Africa experienced a significant decrease in rainfall. This transition zone between the Sahara Desert to the north and the tropical area to the south became even more arid, causing a sharp decline in agricultural production in this region.