Listed are Meteorological events that happened on April 11:
A big April snowstorm in the northeast dropped 12 inches at New York City, 24 inches in parts of New Jersey and 18 inches in parts of Massachusetts.
Destructive thunderstorms swept across central Texas producing two killer tornadoes, both at night. A 12-year old boy died in one of five homes destroyed at the south edge of Colorado City in Mitchell County. At least one woman was killed in her rural home southwest of Cottonwood in Callahan County.
Escondido, CA dropped to 30° setting a record for their coldest April temperature.
It snowed 3 inches at Victorville, CA; their greatest daily snowfall for April and the latest measurable snowfall for the season.
A magnitude 3.8 earthquake shook parts of central Oklahoma on the evening of April 11, 1952. This tremor, centered in southeastern Canadian County, might be considered an aftershock to the magnitude 5.0 quake that shook the same area two days earlier, the 9th. According to the Oklahoma Geological Survey, the magnitude 5 quake is the strongest Oklahoma earthquake on record. Two additional, 3.8 aftershocks, would hit the same area four days later, on the night of April 15th.
Santa Ana, CA dropped to 31°; their lowest temperature recorded in April.
The Palm Sunday Tornado Outbreak wrecked havoc across six states from Wisconsin and in a 450-mile swath west-to-east from Clinton County, Iowa, to Cuyahoga County, Ohio, and a 200-mile swath north-to-south from Kent County, Michigan, to Montgomery County, Indiana. Officially, an estimated 51 tornadoes (very possibly more) killed as many as 271 people with over 3,100 others injured. 11 tornadoes swept across 20 Indiana counties killing up to 137 people. 72 people died in Culver, IN alone. Dunlap, IN was devastated as a pair of massive tornadoes smashed through a mobile home park and a nearby subdivision. This is Indiana’s worst tornado outbreak on record. Tornadoes occurred well after midnight.
The volatile weather system began spawning thunderstorms across Iowa and western Illinois shortly before noon. The rapid change in the mid-morning prompted the Severe Local Storms Center (SELS) in Kansas City, MO to issue a Severe Weather Forecast for an area extending from northeastern Missouri to north central Indiana at 1045 CST. Further organization of the low pressure system and its movement rapidly northeast along with other indicator factors gave SELS forecasters concern that the danger zone was likely to be further north and northeast than first anticipated. A new Severe Weather Forecast, calling for severe thunderstorms, high winds, damaging hail and possible tornadoes are likely, was issued at 1pm CST. Note that in the 1960s, these forecasts were issued to the local Weather Bureau offices who then warned the public as needed. Also, this was the highest severity level forecast that could be issued by SELS. A tornado warning could not be issued until a tornado had been positively identified by either human sighting or identified on radar. Although no F5’s were officially reported, at least 22 were rated as F3 or F4. The outbreak lasted 11 hours and is among the most intense outbreaks in terms of number, strength, width, path, and length of tornadoes ever recorded.
This is the third deadliest day for tornadoes on record, behind the Super Outbreak of 4/3/1974, and the outbreak that included the Tri-State Tornado of 3/18/1925.
Damage totaled more than $238 million 1965 dollars. Indiana sustained property damage estimated at $145 million dollars, while Michigan reported $51 million dollars and Ohio at $42.5 million dollars. Dr. Ted Fujita discovered suction vortices during the Palm Sunday tornado outbreak. It had been believed the reason why tornadoes could hit one house and leave another across the street completely unscathed was because the whole tornado would "jump" from one house to another. However, the actual reason is because most of the destruction is caused by suction vortices: small, intense mini-tornadoes within the main tornado. The outbreak did leave positive legacy, however, as the government's role in warning the public was transformed. Some things that came out of the disaster: spotter programs, NOAA Weather Radio, and increased public awareness programs.
Here are the official forecasts/statements from the Severe Local Storms Center:
SEVERE WEATHER FORECAST NUMBER 68
ISSUED 100 PM CST APRIL 11, 1965
EXTREME SOUTHERN WISCONSIN
EXTREME EASTERN IOWA
PORTIONS OF NORTHERN ILLINOIS
A FEW SEVERE THUNDERSTORMS WITH LARGE HAIL DAMAGING WINDS AND ONE OR TWO TORNADOES ARE EXPECTED FROM 1 PM UNTIL 6 PM CST THIS SUNDAY AFTERNOON AND EVENING IN AN AREA BOUNDED BY THE POINTS 40 MILES SOUTH OF BURLINGTON IOWA TO 50 MILES WST OF LONE ROCK WISCONSIN TO MILWAUKEE WISCONSIN TO 40 MILES SOUTH EAST OF CHICAGO ILLINOIS BACK TO THE POINT 40 MILES SOUTH OF BURLINGTON IOWA.
WOOD ... 1906Z
SEVERE WEATHER FORECAST NUMBER 69
ISSUED 420 PM CST APRIL 11, 1965
PORTIONS OF NORTHERN INDIANA
PORTIONS OF SOUTHERN MICHIGAN
PORTIONS OF NORTHWEST OHIO
SCATTERED SEVERE THUNDERSTORMS WITH A TORNADO OR TWO LARGE HAIL AND LOCALLY DAMAGING WIND STORMS ARE EXPECTED IN AN AREA ALONG AND 60 MILES EITHER SIDE OF A LINE FROM 10 MILES NORTHWEST OF LAFAYETTE INDIANA TO DETROIT MICHIGAN FROM THE PRESENT TIME TIL 8 PM CST THIS SUNDAY EVENING.
TORNADO FORECAST NUMBER 66 IS CANCELLED
CRUMRINE .... 2230Z
SEVERE WEATHER FORECAST NUMBER 71
ISSUED 6 PM CST APRIL 11, 1965
PORTIONS OF CENTRAL MICHIGAN
SCATTERED SEVERE THUNDERSTORMS WITH A TORNADO OR TWO LARGE HAIL AND LOCALLY DAMAGING WIND STORMS ARE EXPECTED IN AN AREA ALONG AND 60 MILES EITHER SIDE OF A LINE FROM 20 MILES SOUTHEAST OF MUSKEGON MICHIGAN TO 60 MILES EAST OF GLADWIN MICHIGAN FROM THE PRESENT TIME TIL 8 PM CST THIS SUNDAY EVENING.
CRUMRINE .... 0009Z
SEVERE WEATHER FORECAST NUMBER 72
ISSUED 710 PM CST APRIL 11, 1965
PORTIONS OF INDIANA
THE NORTHWEST PORTION OF OHIO AND
PORTIONS OF SOUTHEAST MICHIGAN
SCATTERED SEVERE THUNDERSTORMS WITH A FEW TORNADOES LARGE HAIL DAMAGING WIND STORMS ARE EXPECTED IN AN AREA ALONG AND 60 MILES EITHER SIDE OF A LINE FROM 60 MILES SOUTHWEST OF INDIANAPOLIS INDIANA TO 20 MILES SOUTH OF DETROIT MICHIGAN FROM 8 PM TO MIDNIGHT CST THIS SUNDAY EVENING.
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 South Dakota.
On this date through the 14th, an Ice storm at St. John’s, Newfoundland Canada produced accumulations up to 6 inches thick on power lines. Power outages left 200,000 residents of Avalon Peninsula in the dark and cold.
Ten days of flooding in the northeastern U.S. finally came to an end. Damage from flooding due to rain and snow melt ran into the billions of dollars. The collapse of the New York State Thruway Bridge over Schoharie Creek claimed ten lives.
Many cities in the western U.S., some in California, reported new record high temperatures for the date. Afternoon highs of 95° at Sacramento, CA and 96° at Bakersfield, CA were the warmest of record for so early in the season.
Many cities in the south central and eastern U.S. reported new record low temperatures for the date. Lows of 25° at Conway, AR, 29° at Dallas/Fort Worth, TX, and 22° at Ozark, AR, were April records. Lows of 26° at Hot Springs, AR and 31° at Shreveport, LA equaled April records.
While showers produced heavy rain over much of the northeastern U.S., heavy snow blanketed northern Maine, with 13 inches reported at Telos Lake. Strong southwesterly winds accompanying the rain and snow gusted to 68 mph at the Blue Hill Observatory outside of Boston, MA. Rainfall totals of 1.04 inch at Pittsburgh, PA and 1.52 inches at Buffalo, NY were records for the date.
A strong Pacific storm dumped heavy snow across the northern Colorado Rockies. Accumulations of 6 to 15 inches fell at lower elevations in and around Denver and up to almost two feet in the foothills west of town. Specific snowfall accumulations included: 21 inches at Idaho Springs, 19 inches at Aspen Springs, 15 inches at Arvada, 14 inches at Rollinsville, 10 inches at Boulder, 8 inches at Aurora and 7.3 inches at Stapleton Airport.
In North Dakota, the Red River was more than 20 feet above flood stage, its highest level in 150 years. The flooding was caused by rain and snow that began the previous month.
The Mississippi River reached its third highest flood on record, affecting several homes and businesses. High water also forced the closure of some highways. On this date, the Mississippi River crested at Lake City, MN: 19 feet and Wabasha, MN: 16.5 feet.
Major snowfall across the Midwest dumped up to two feet of snow on Southern Iowa and 13 inches at Galesburg, IL. The snow forced postponement of several minor league baseball games across the area, as well as cancellation of the Chicago Cubs game.
An intense spring blizzard dumped heavy snow and freezing rain as it moved out of the Rockies to the northeastern Plains of Colorado. High winds and heavy snow buffeted parts of the Front Range. Up to 18 inches of snow caused drifts as high as 10 feet. Denver International Airport closed for the first time in its six year history. 220,000 people were without power in the worst outage in Xcel Energy history. The storm resulted in one of the worst windstorms in Kansas history.
Record heat settled over southern British Columbia in Canada over Easter weekend with Victoria shattering long-term record highs. The 76° in downtown broke a century old record for the day while at the airport; the high of 74° broke a 50-year record.
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