South Dakota Weather History and Trivia
April

April 1 -

Due to poor farming practices (especially in third world country's) the amount of the earth's precious topsoil that is either being blown away or washed into the sea across the earth is estimated to be around 75 billion tons per year. That is ten times the rate at which new topsoil is being generated.

April 2 -

An early Spring storm brought hail and damaging winds to the tri-state area on the afternoon of April 2nd, 1982. That evening temperatures plunged rapidly with the passage of a strong cold front leading to a snowstorm across much of South Dakota. During the afternoon severe thunderstorms produced hail up to 1 inch in diameter at Harrisburg in Lincoln county and portions of northwest Iowa. Strong sustained winds at 50 mph moved across south Dakota and into southwest Minnesota and northwest Iowa, with a peak wind of 72 mph at Yankton.

After reaching afternoon highs in the 70's temperatures plunged into the 30's during the evening. The rapid drop in temperature turned areas of rain into areas of freezing rain and snow. Heavy ice accumulations snapped power poles in McCook county in southeast South Dakota leading to extensive power outages. 2 to 4" of snow fell in western and southern South Dakota although amounts were light in NW Iowa and SW Minnesota. Winds at 20 to 40 mph caused drifts to 4 feet deep and blizzard conditions in rural areas.

April 3 -

The coldest temperature ever recorded during the month of April at Sioux Falls occurred on this date in 1936, when the temperature fell to just 4 degrees F above zero.

April 4 -

It often seems like the Northern Plains have got to be the windiest place in the United States. In fact, no recording station in South Dakota, North Dakota, Nebraska, or Iowa even makes the top ten. The windiest place is Blue Hill, MA with an annual average wind speed of 15.4 mph. Second on the list, Dodge City , KS at 14.0 mph. #4 is Rochester, MN at 13.1 mph. As a side note the Windy City...Chicago...is not in the top ten.

In actuality, the windiest recording station in the U.S. is atop Mt Washington in New Hampshire with an annual wind speed average of 35 mph. However, it does not qualify due to its high elevation.

April 5 -

During the summer months, if you ever want to know what the temperature is at night, just listen to the crickets. Count the number of cricket chirps in 14 seconds and add 40. This will give the temperature at the ground in Fahrenheit. The temperature will probably be 2 to 3 degrees warmer around your head. The chirp of the cricket is influenced or controlled to a degree by the air temperature. Thus, a crickets chirp is a fairly reliable estimate of the temperature.

April 6 -

The heavy rains that pour out of thunderstorms really start as snow inside the storm and then melt as it falls into the warm lower layers near the surface. On April 6th, 1976 the Black Hills experienced the fury of the thunderstorm and a bit of an unusual snow. During the afternoon hail piled up to 3" deep in Hot Springs while elevations above 5000 feet in the Hills received over an inch of snow from the storm.

April 6 -

The earliest last freeze on record in Sioux Falls occurred on this date in 1977 when the temperature fell to 23 degrees F.

April 7 -

All other factors being equal the structural damage potential of the wind increases with the square of the wind speed. That is, a 60 mph wind can exert 4 times more pressure on an object than a wind of 30 mph can.

April 8 -

We tend to think that the relative humidity can go no higher than 100%. In fact, inside of a cloud a condition known as supersaturation can occur where the relative humidity can reach 102-103%. This condition is caused by the different attractive properties of ice and water and results in the growth of cloud droplets.

April 9 -

Here is a piece of weather folklore for you "circle around the moon, it will rain or snow soon". The circle that you can sometimes see around the moon is caused by refraction of light through ice crystals. These ice crystals are quite high in the troposphere and are usually associated with a thin layer of cirrus clouds. Often this layer of ice crystals will precede a developing storm by 24 to 36 hours. The circle does not mean it will rain or snow, but it can be an indicator that there may be a chance of precipitation in the next couple of days.

April 9 -

On April 9th, 1938 the temperature dropped below freezing. That in itself is nothing special, but the fact that the temperature at Sioux Falls did not drop below freezing again until October 23rd, 1938, means that it was the longest such stretch on record. This gave the Sioux Falls area 197 days freeze free days in a row.

April 10 -

You have probably noticed a distinct smell in the air as a rain shower approaches. You may have also heard the weather saying "the flower's perfume is strongest before the storm". Well, these two ideas are related. As a storm approaches the air pressure is most likely falling. This lower air pressure allows scents from plants and other sources to be more readily released. The end result is a mixture of many different scents giving a distinctive smell.

April 11 -

On April 11th, 1978 high winds battered nearly the entire state of South Dakota. The high winds, accompanying a rapidly moving cold front, produced gusts of 75 mph at Phillip, 69 mph at Rapid City, and 62 mph at Sioux Falls. Other areas generally had gusts of 45 to 65 mph. The strong winds knocked down trees and power causing pockets of power outages across the state.

April 12 -

On the morning of April 12th, 1970 a strong winter storm was affecting the northern and western 2/3rds of South Dakota. Heavy snow fell throughout the morning hours dumping over a foot of snow over a large area of the state. Winds whipped the snow into 2 to 4 foot drifts across much of northern South Dakota. The Aberdeen area was the hardest hit with around 17 inches reported.

While southeast South Dakota, southwest Minnesota, and northwest Iowa did not feel the effects of the storm, east central South Dakota was not as fortunate. Freezing drizzle and freezing rain resulted in heavy icing in east central South Dakota causing extensive damage. The ice storm caused power outages to 20 to 80% of the rural electric service in the area.

April 13 -

April 13th and 14th, 1986 heavy snow and strong winds produced blizzard conditions over nearly all of South Dakota as well as portions of northwest Iowa and southwest Minnesota. A foot or more of new snow was common across north central South Dakota, with 15" reported at Gettysburg and Eureka. Over most of the remainder of the state 3 to 8" of snow was reported. To make matters worse winds of 30 to 45 mph with gusts of 90 mph reported at Mitchell and Yankton caused areas of blowing snow. Sections of northwest Iowa were also affected by the storm with 1 to 3 inches of new snow and strong winds. The high winds blew the roofs off of several buildings in Sioux City and the surrounding area.

Drifts as high as 15 feet were common across central sections of South Dakota forcing the closure of much of Interstate 90. The storm also took down over 100 power poles in the west and resulted in the loss of livestock in central SD. Livestock losses of up to 35% in some herds was reported with a price tag of several million dollars. Many people in central South Dakota thought it was the worst blizzard that they had ever experienced.

April 14 -

A heavy snowmelt in addition to several significant rain events led to widespread flooding across northeast South Dakota during April of 1986. Lake Poinsett was 4 feet over full and water across the area was as high as many residents could ever remember. Many roads and tens of thousands of acres of farmland were under water. Many homes and businesses across the northeast suffered water damage from the flooding. Most of northeast South Dakota was declared a state and federal disaster area with, at least, 3 million dollars in damage from the high water.

April 15 -

Strong winds and blowing dust made life miserable across South Dakota as well as western Minnesota and Iowa during the first half of April in 1971. Winds of around 60 mph on several different days early in the month were reported across the area. Mitchell, South Dakota reported gusts of 75 mph on the 1st and the 10th of April, 1971. Much of the area was well below normal for precipitation since the turn of the year. This left the Northern Plains in a precarious position. The dryness of the topsoil made it subject to blowing and the strong winds were taking advantage of it. The high winds caused widespread blowing dust which at times reduced visibilities to near zero. the strong winds also blew the winter wheat out of the ground in portions of western South Dakota prompting some to fear a return of the Dust Bowl of the 1930's. Fortunately such fears proved unfounded as conditions began to improve by early May.

April 16 -

A deepening low pressure system moved northward out of Nebraska and across western South Dakota on April 16th, 1976. The storm produced extremely strong winds across eastern South Dakota, southwest Minnesota, and northwest half of Iowa. Winds of 60 to 80 mph were reported across the area with gusts over 90 mph in southwest Minnesota. Some recorded wind speeds included 62 mph at Sioux Falls, 70 mph at Brookings, and 82 mph at Watertown.

During this long day of high winds many buildings were damaged and many roofs were blown off. At the Sioux Falls and Huron airports a couple of planes were overturned. Across southwest Minnesota many trees were uprooted and several trucks were blown off of the highway. Across the area many barns, outbuildings, sheds, and older structures were completely demolished. In 2 separate incidents in northwest Iowa downed power lines set fire to several barns resulting in the loss of property and livestock.

April 17 -

Wettest city in the United States? That distinction belongs to Yakutat, Alaska, which averages 160.38 inches of precipitation a year (based on 1970-2000 climatological normals).  Other cities among the top 10 include Ketchikan, Alaska, with 137.40 inches, and Hilo, Hawaii, which averages 126.27 inches of precipitation a year.  The top city within the 48 contiguous United States is Mount Washington, New Hampshire with 101.91 inches per year, followed very closely by Quillayute, Washington, which averages 101.72 inches per year. By comparison Sioux Falls averages a paltry 24.69 inches a year.

April 18 -

A cluster of thunderstorms developed over South Central South Dakota on April 18th, 1981. The thunderstorms were extremely efficient rain producers as 4 and one-half inches fell in one hour along with pea to marble size hail. Flash flooding resulted from the heavy rains...washing away fences and sheds across Bennett, Todd, and Mellette counties. The rain water swept the hail into drifts with some areas reporting 10 to 12 foot hail drifts in ravines.

April 19 -

April 19th into the 20th, 1985 severe thunderstorms erupted across central and eastern South Dakota. Numerous reports of high winds were received during the outbreak. One particularly strong storm carved a path of destruction from Pierre to Mobridge. The storm blew over several mobile homes in the Pierre area and knocked boats off of their trailers. The Pierre airport reported a gust of 98 mph. The high winds blew down 10 hangers and destroyed 25 to 30 planes. The strong winds lasted for more than 20 minutes in Pierre resulting in more than a million dollars in damages. The storm continued to the north with wind gusts of 80 to 100 mph knocking down trees and tearing off roofs resulting in hundreds of thousands of dollars in additional damages.

At the same time numerous thunderstorms were also ripping across eastern South Dakota. Thunderstorms winds of 50 to 75 mph were common and, at least, 10 separate tornadoes were reported on the 19th and 20th. One tornado about 6 miles north of Vermillion, South Dakota lifted a 40 foot by 40 foot building then tossed it over two grain bins and on top of another building. A tornado about 1/4 of a mile wide moved north of Hurley (in Turner county) on the 20th. The tornado extensively damaged several farms blowing down barns, silos, and sheds. At one farm insulation from the roof was reportedly found inside of closed drawers in a bedroom.

April 20 -

A blizzard beginning on April 18th, 1992 lasted into the 20th across the Black Hills of South Dakota. Heavy wet snow and strong winds created blizzard conditions in the northern Black Hills that led to a major power outage. About 2000 households were without power for over 4 hours in some areas around Lead/Deadwood. Snow amounts of 2 feet were common with 30 inches falling at Lead causing major traffic problems. Northwest winds gusted to over 65 miles an hour at Rapid City and to around 50 mph in the Hills .

April 21 -

A slow moving area of low pressure which had brought heavy snow to western South Dakota affected eastern South Dakota on April 21st and 22nd, 1992. As the large storm moved east across the state it brought heavy snow and ice accumulations with it. Freezing rain or sleet preceded the snow across much of the east laying down a slick glaze of ice. On top of the icy roadways 6 inches to a foot of wet snow piled up making traveling very hazardous. The slick roads resulted in many accidents across eastern South Dakota as well as northwest Iowa and southwest Minnesota. Winds gusting to around 50 mph only made travel more difficult. Many towns in southwest Minnesota lost power due to the heavy icing...some areas were without electricity for over 5 hours. Some snowfall amounts across the east included 10 to 12 inches in the Marion and Elk Point areas in Southeast SD and around 9 inches near Vermillion.

April 22 -

With a fresh blanket of snow from a recent snowstorm helping to keep the air cool the high temperature at Sioux Falls on April 22, 1992 was a measly 31 degrees. This is the latest below freezing high temperature on record in Sioux Falls.

April 22 -

On April 22nd, 1970 a major winter storm was finally exiting South Dakota after 4 days of battering the state. The slow moving storm began affecting western South Dakota on April 18th, 1970 dumping heavy snow in the Black Hills through the 20th. Amounts of up to around 2 feet were reported. Lead reported 22 inches of new snow which when added to the 1969-70 seasonal snowfall set an all-time seasonal snowfall record for Lead at 206.6 inches. The old record was 187.8 inches which fell in the 1954-55.

Snow accumulations in the lower elevations across the west and north were as high as 1 1/2 feet. The tri-state area received the lightest amounts in the state ranging from 2 to 3 inches. Southwest Minnesota and northwest Iowa were largely spared from the storm although strong winds on the 22nd did cause some damage in portions of northwest Iowa.

April 23 -

It is estimated that the water involved in all of the world's clouds, rain, and snow makes up less than three-tenths of 1% of the total free water in the atmosphere and on the earth's surface. On the other hand ice caps and glaciers hold about 2% of the total.

April 24 -

We don't tend to think that the atmosphere has weight. In actuality, the atmosphere weighs plenty. The weight of the atmosphere is what causes atmospheric pressure...this is simply the amount of pressure or force that the atmosphere is putting on a particular spot. All told the earth's atmosphere weighs around 1.5 million billion tons.

April 25 -

A major Spring storm affected the Northern Plains from April 25th through the 29th, 1984. The storm brought heavy snow and strong winds to western South Dakota paralyzing a third of the state for over three days. Snow amounts were heaviest in the northern Black Hills where 67 inches fell at Lead and 44 inches fell at Deadwood. The storm resulted in the loss of large numbers of livestock with, at least, 13,000 cattle and 15,000 sheep falling victim to the storm. The heavy wet snow wreaked havoc with the electricity as 10,000 people were without power at one time or another....some areas north of Rapid City to the North Dakota border were without power for up to 1 and a half days. After the heavy snow...strong winds produced a major blizzard. The storm resulted in several million dollars worth of damage and losses across western South Dakota.

As heavy snow pounded western SD on the 26th thunderstorms ripped across the eastern portion of the state and into northwest Iowa and southwest Minnesota. Two separate lines of storms moved east across the area producing golf ball size hail and winds in excess of 60 mph in some areas. Funnel clouds were sighted near Worthington, MN, but only straight-line wind damage was reported in the area. By April 29th, 1984 the thunderstorms gave way to snow across the tri-state area as 3 to 7 inches blanketed the region.

April 26 -

Intense thunderstorms swept across southeast South Dakota, southwest Minnesota, and northwest Iowa on April 26th, 1986. Baseball size hail fell in a 15 mile wide swath from near Pickstown to Scotland, South Dakota. The large hail caused extensive damage to windows, roofs, siding, and vehicles in the path of the storm. Wind gusts of 70 to 80 mph and rain amounts of 2 or more inches in a short period of time (including 5 inches at Centerville) were reported in southeast South Dakota.

Several tornadoes moved across northwest Iowa including one that moved across part of Lyon County destroying several farmsteads. Another tornado moved through Lyon County, Iowa into Nobles County, Minnesota damaging, at least, 16 separate farms. Yet, another tornado touched down briefly on the south side of Okebena in Jackson County destroying or damaging several houses.

April 27 -

What's the cloudiest city in the United states? Well, as you might expect the cloudiest area is the Pacific Northwest. There is a tie between Astoria, Oregon and Quillayute (pronounced Key-a-ute), Washington with 240 cloudy days a year. Seattle, Washington live up to its reputation coming in 4th with 227 cloudy days per year. 6 of the 10 cloudiest cities are in Washington or Oregon.

April 28 -

On April 28th, 1994 winter returned to eastern South Dakota western Minnesota and western Iowa just three days after temperatures in the 80s and severe thunderstorms ripped across the region. A strong area of low pressure moved across the plains states and heavy snow developed across the tri-state area. Snow accumulated in the 5 to 12 inch range across eastern South Dakota with 5 to 10 inches in southwest Minnesota and northwest Iowa. Heavy snow fell to the crashes of thunder at Sioux Falls where 4 inches accumulated in one hour. The 10.5 inches that piled up in Sioux Falls was the most ever recorded for so late in the season.

April 28 -

On April 28th, 1910 the mercury climbed all the way to 98 degrees at Sioux Falls. This is the warmest temperatures ever recorded in Sioux Falls during the month of April.

April 29 -

At any given moment 1000 to 2000 thunderstorms are occurring around the world. All those storms are also producing a lot of lightning. It is estimated that lightning strikes the surface of the earth about 100 times a second.

April 30 -

April 30th, and May 1st, 1967 a late season blizzard swept across the northern plains. One of the latest major storms on record for the state began late on the April 30th and continue into the first day of May. Snowfall across western South Dakota was generally in the 5 to 12 inch range with 16" at Lemmon and 30" in the northern Black Hills. Winds of 40 to 50 mph reduced visibilities to near zero and piled the snow into 4 to 5 foot drifts. Livestock losses were estimated at around 5% from the storm.

Eastern South Dakota, Southwest Minnesota, and Northwest Iowa only received light snow.

April 30 -

April 30th, 1992 the temperature climbed to 92 degrees at the Sioux Falls airport. While quite warm for April it is not even a record high for the date...however it turns out to be the warmest day of the year. This is the only time on record for Sioux Falls when the warmest temperature of the year has occurred in April.

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