From October 31st through November 2nd, 1991 a blizzard swept through northwest Iowa, southeast South Dakota and southwest Minnesota. Snow accumulated up to 16 inches in some areas. The snow, combined with winds of 60 miles an hour at times, produced widespread blizzard conditions. Interstates 29 and 90 as well as most other roads in the tri-state area were closed as a result of the storm.
To give you an idea of how much of a summer maximum the Northern Plains has in the precipitation department let's look at a few stats. Sioux City averages 3.71 inches of precipitation in the month of June. The average precipitation for the months of November, December, January and February combined is just 3.12 inches.
In November of 1963, no snow fell in Sioux City. This is the record for the least amount of snowfall for this month. In addition, several years including 1972 saw only a trace of snow. The normal snowfall for the month of November for the Sioux City airport is near 4 and a half inches.
The dry conditions of October 1992 were replaced by above normal precipitation in November. Flooding was evident in north central Iowa from November 4th through November 7th 1992. Statewide precipitation amounts totaled around 4.42 inches or 293% of the normal 1.51 inches. Precipitation was observed somewhere in the state on all but five days of the month.
November is in a way the traditional start to the snow season across much of the Northern Plains. From 1889 to 1994 the first measurable snowfall for Sioux City occurred 64 times in the month of November. The earliest measurable snowfall occurred on September 30th, 1961 while the latest snowfall fell on December 25th, 1933.
An early season snowfall developed in the wake of a cold frontal passage over northwestern Iowa on November 6th, 1990. Many areas received two to five inches of wet snow, with a few areas reporting six to seven. The snow stuck to trees causing some tree damage. A piece of good news is that warm ground temperatures kept most roadways from becoming slippery.
Weather related disasters can carry a huge economic toll. In fact, between 1988 and 1993 there were at least seven weather- related disasters in the United States causing damage of $1 billion dollars or more.
The events include: 1993 summer floods ($12 billion); Blizzard of 1993 along U.S. east coast ($6 billion); Hurricane Andrew ($25 billion); Hurricane Iniki ($1.8 billion); Hurricane Bob ($1.5 million); Hurricane Hugo ($7.7 billion); and the Drought of 1988 ($40 billion).
In the hydrometeorological model of the earth's water cycle, river water flows downhill to reach the world's seas. This simple idea has become quite a bit more difficult lately. In the last 40 years around 15,000 large dams have been constructed around the world. These dams intercept about 15% of the global runoff, much of which is stored in reservoirs for agricultural and urban use.
A major blizzard struck northwest Iowa, the eastern two- thirds of South Dakota and western Minnesota on November 9th, 1977. A strong area of low pressure moved from northeast Colorado across north central Iowa bringing a variety of problems to the region. On November 8th, 1977 the storm began as rain with temperatures in the 50's in most areas. The tri-state area was then coated with freezing rain and sleet before the precipitation changed to snow.
Up to six inches of snow fell in northwest Iowa with wind gusts up to 65 miles an hour making travel impossible. Amounts were generally 4 to 12 inches across eastern South Dakota with gusts to 70 miles an hour. Portions of western Minnesota were the hardest hit with snow amounts up to 14 inches and winds howling up to 80 miles an hour. Drifts piled up to 8 feet deep across portions of Minnesota. More than 200 people were stranded in automobiles on I-29 between Sioux City and Onawa. Two of the stranded vehicles were trucks transporting turkeys. As the temperatures plunged, about half of the turkeys were prematurely frozen. The winds also blew down trees and several radio towers.
Historically, November 10th has been a slow weather day around the tri-state area, but not so in the Great Lakes. On November 10th, 1975, the huge iron ore freighter, the Edmund Fitzgerald sank in the icy waters of Lake Superior several miles off Whitefish Point, Michigan. The Fitzgerald was 729 feet long and carrying 26,000 tons of iron ore to the auto factories of the east.
West and northwest winds of 70 to 100 miles an hour produced 20 to 30 foot waves across Lake Superior which led to the Fitzgerald's demise. No one knows exactly sure how the ship sank, but somehow it broke in two and sank so fast the captain did not have time to relay a MayDay. Twenty-nine crew members died.
The first significant snowfall of the 1981-1982 winter season occurred on November 11, 1981. One to three inches of snow fell across northwest Iowa which was preceded by rain and sleet. Strong winds caused considerable blowing and drifting snow. Many east and west highways were drifted over with snow on top of a heavy ice buildup. A multiple car pile-up on the Veterans Memorial Bridge spanning the Missouri River between Sioux City and South Sioux City caused the span to be blocked for 90 minutes. November 11th happens to also be the average date for the first snow for Sioux City.
You may have heard the saying "it was even 100 degrees in the shade." Well, to be accurate thermometers must be read in the shade. This is because an incredible number of air molecules constantly bombard the thermometer transferring energy to or away from it. If the air is warmer than the thermometer the liquid in the bulb expands and rises up the tube and if the air is colder the liquid contracts and sinks in the tube. It is impossible to measure air temperature accurately in direct sunlight because the thermometer will absorb radiant energy from the sun as well as energy from the air molecules. The additional energy from the sunlight will cause the liquid to continue to rise giving an improper reading. Therefore, to accurately measure air temperature the thermometer must be kept in the shade.
The winter of 1967-1968 was pretty paltry by snowfall standards. That winter only 7.9 inches of snow accumulated in Sioux City. That is the lowest snow total for any winter season on record. In contrast, the most snow ever recorded for a winter season occurred in 1916-1917 where 72.8 inches fell.
On November 14th, 1959 during a major early season cold spell the temperature in Sioux City fell to -9 degrees. Not only is that a record low for the day, it is also the coldest temperature on record in Sioux City for the month of November. The low of -9 degrees was also equalled on several other days in November.
Although we think of the severe weather season as traditionally in the spring and summer, plenty of severe weather battered a large portion of the eastern two-thirds of Iowa on November 15th, 1988. Lightning struck a power substation in Mason City knocking out power to 2100 homes. Numerous tornadoes touched down in Monroe, Wayne and Appanoose counties. In addition, tornadoes caused significant damage northeast of Ottumwa and near Waverly. Snow fell behind the front in northwest Iowa where three to six inches was common.
Wind power has become an increasingly attractive way to generate electricity as fossil fuels continue to decrease in quantity. Wind power is renewable, clean, efficient, and unlike solar energy can be utilized at night. However, there are drawbacks. For a wind turbine to produce electricity there must be wind, and not just any wind, it must be a steady flow of air neither too weak nor too strong. A slight breeze will not turn the blades and strong gusts could damage the equipment.
In a steady wind of 20 miles an hour the wind turbine can convert between 30 to 40 percent of the available wind energy to electricity. Their efficiency increases with both the wind speed and the size of the rotor blade.
Intense low pressure developed over the plains during the night of November 16th and 17th, 1994. As the low moved into South Dakota, strong winds developed ahead of its associated cold front. Northwest Iowa had frequent gusts of 50 to 55 miles an hour. Two tractor-semitrailer trucks were overturned on I-80 in Guthrie County. Spotty damage to property was reported over the northwest third of the state. The high winds continued through the 18th with winds gusting to 58 miles an hour at Estherville and 57 miles an hour at Spirit Lake.
Annual weather losses in the United States are estimated to be as high as $34.5 billion with $22 billion in the agricultural industry alone. The next highest monetary damage in any industry is the $2.7 billion dollars lost by the construction industry. Preventable losses in agriculture are an estimated $9.7 billion, with $894 million preventable in construction. Money estimated to be saved by improved forecasts and technology in the National Weather Service is estimated to be two to three times greater than all losses to the general public combined.
Low pressure located in Oklahoma on November 18th, 1975, moved north across Kansas, Iowa and into Wisconsin by the 20th. What began as light rain across the tri-state area quickly turned to snow on the 19th. In the late afternoon of the 19th and morning of the 20th, heavy snow and blizzard conditions were found across northwest Iowa. Eight to ten inches of snow was common with winds exceeding 50 miles an hour. Northwest Iowa was paralyzed with all roads blocked, some drifts six to eight feet high, numerous traffic accidents and schools closed.
To the northwest of the tri-state area, northern and western portions of South Dakota were hammered by a strong winter storm on November 19th and 20th, 1977. The storm move rapidly from Colorado across eastern Nebraska and into Minnesota producing widespread snowfall across the area. Snow amounts across northern South Dakota exceeded 5 inches with amounts of up to 15 inches reported. Winds of 50 miles an hour produced blowing snow which greatly reduced visibilities and drifted snow up to 5 feet deep. The storm also caused the derailment of a freight train in northeast South Dakota.
Southeastern South Dakota was hit with heavy snow on November 21st and 22nd, 1979. Snowfall totals were in the 6 to 13 inch range with generally lesser amounts across northwest Iowa and southwest Minnesota. Sioux Falls reported the highest storm total at 13 inches. Sioux Falls' 24-hour total on the 21st-22nd of 11.8 inches is the heaviest 24-hour snow total in the month of November on record for the city. Moderate winds of 20 to 35 miles an hour made travel difficult at times.
On November 22, 1983, a snowstorm dumped two to six inches of snow over a large part of northwest, southwest and central Iowa. In addition, freezing rain accompanied the snow in some locations. The result was extremely hazardous roads and highways, with a glaze of ice underneath the snow. Power lines were downed by the ice, and many rural communities lost power for hours.
Late Fall and Winter is the prime time of year for fog across most of the northern plains. In an average year Sioux City and the surrounding area will have 10 to 20 days with dense fog. Dense fog is defined as visibilities less than 1/4 mile. Of course, favored areas, such as locations near rivers and in low lying areas will see more days with dense fog than surrounding areas.
One of the foggiest places in the Lower 48 states is the appropriately named Cape Disappointment on the U.S. west coast where they have around 2,552 hours per year of foggy weather. That means that roughly 1/4 of the year is foggy there.
During the late afternoon and night of November 24th, 1993, a strong storm system swung out of the southern plains across Iowa. Snow began in earnest over northwest Iowa during the late afternoon hours. The period of heaviest snow occurred during the mid evening hours until after midnight. Snowfall over northwest Iowa was generally in the five to nine inch range. Some of the heavier totals included ten inches at Rock Valley, nine inches at Everly and eight inches at Onawa. Considerable drifting occurred as winds averaged 15 to 30 miles an hour. Reports of drifts in excess of three feet were common. The fresh snow cover resulted in disrupted holiday travel during Thanksgiving.
Some people believe that sleet and freezing rain are the same thing. In actuality, sleet and freezing rain are quite different. Sleet, also known as ice pellets, are completely frozen raindrops that bounce when they hit the surface. Freezing rain is still liquid when it hits a subfreezing surface. It then quickly freezes covering everything with glaze ice.
November 26th through the 28th, 1983 a strong winter storm rocked portions of the Northern Plains. The storm began as light snow across southeast South Dakota with freezing rain across portions of Iowa and southern Minnesota. At the height of the storm heavy snow piled up and thunder and lightning were heard in some areas. Snow amounts of 6 to 18 inches buried southeast South Dakota, 10 inches plus fell in southwest Minnesota and 6 to 16 inches immobilized northwest Iowa.
Winds up to 50 miles an hour made travel impossible across the area. In fact, only snowmobiles were able to traverse any distance in the Yankton and Vermillion areas. Many roads had drifts as high as 8 feet stranding hundreds of vehicles. The weight of the snow and high winds collapsed a warehouse in Sioux City with damage estimated at $500,000 dollars.
On November 27th through the 29th, 1987, an early season snow storm hit western Iowa, northeast Nebraska and southeast South Dakota. Damage was mainly limited to trees and power lines. Automobile accidents were numerous and traffic was slowed to a crawl. On November 26th and 27th of 1988, heavy snow was blown by high winds creating blizzard conditions across portions of southeastern South Dakota and much of Minnesota. Amounts around 6 inches were common... especially in southwest Minnesota, but the real problem was the combination of wind and snow. Winds gusting to over 50 miles an hour produced drifts up to 6 to 7 feet deep forcing the closure of Interstate 90 from Sioux Falls to well into Minnesota. The storm left thousands of travelers stranded across the area.
On November 27th 1994, a heavy snow event rocked northwest Iowa with 8.3 inches reported in Sioux City. The heaviest snow totals came from extreme northwest Iowa with Rock Valley reporting 12.5 inches while Rock Rapids recieved 12.0 inches. Winds of 20 to 35 miles an hour caused considerable blowing and drifting snow.
November 1983 stands as the snowiest November on record for the Sioux City airport. 16.5 inches of snow accumulated during November 1983 breaking the old record of 15.1 inches set in 1959. The normal snowfall during the months of December, January and February averages 17.7 inches for Sioux City.
November 28th through the 30th, 1991 the third major snowstorm of the season affected most of the tri-state area. On the 28th a developing area of low pressure moved north out of the southern plains. The storm dumped 4 to 8 inches of snow across the eastern third of South Dakota. Strong winds produced widespread drifting and blowing snow. Snowfall amounts included 6 inches in Sioux Falls and 7 inches in Vermillion.
Conditions in northwest Iowa were even worse. Much of northwest Iowa was glazed with freezing rain on November 29th, 1991 with over 1 inch accumulating in most areas. The weight of the ice damaged trees and power lines in many communities. To add to the problems thunderstorms accompanied the freezing rain. At times a mixture of ice pellets and snow pelted the area. Snowfall amounts totaled in the 2 to 7 inch range. Overall the storm caused millions of dollars in damage in Iowa alone.
A major winter storm rocked eastern sections of South Dakota and northern Iowa on November 30th and December 1st, 1981. The storm began as rain and then changed to freezing rain and sleet before becoming all snow. Winds gusted to over 50 miles an hour producing blizzard conditions. Snow accumulations in southeast South Dakota were generally 8 to 12 inches with 4 to 8 inches across northwest Iowa. In portions of north central Iowa a heavy build-up of ice from the freezing rain combined with strong winds causing power lines to bounce 4 to 6 feet snapping lines and breaking insulators resulting in numerous power outages.