El Nino Events and Their Effects on

La Crosse, WI

 

 

 

The term "El Nino" refers to the warming of the coastal waters along the west coast of South America, usually centered around Ecuador and Peru. This warming causes a shift in the global weather pattern and can produce extended periods of drought or rain. Because this warming frequently occurs around Christmas, local residents called it El Nino, which is Spanish for "boy child", referring to the Christ child.

Normally in that part of the Pacific Ocean the trade winds blow to the west, toward a region of lower pressure centered over Indonesia. These winds drag some of the cool water with them, with that water being warmed by the sunlight and atmosphere as it moves west from. As a result, the surface water along the equator in the Pacific Ocean is cool in the east and warm in the west. In El Nino cases, the exact opposite happens. Higher pressure sets up over Indonesia, causing the winds to now move to the east, and thusly warming the waters in the east. A strong El Nino event usually occurs every 3 to 7 years.

In general, La Crosse will be warmer then normal about 80 to 70% of the time in El Nino years, while preciptation is close to normal. However, a stronger variability takes place the more intense the El Nino event is. In the cases of the moderate to strong events (category 3 and 4), it was warmer 70 to 80% of the time, but if it was colder, it was usually much colder then average.

The intensity scales are based upon how big a warm up occurs along the South American coast. The more the waters warm, the stronger the intensity of the El Nino event

For the following tables, winter temperature and precipitation is for the months of December, January, and February. The seasonal snowfall runs from July through June.

Averages for all years for La Crosse including El Nino events:

Average Winter Temp: 19.7 degrees

Average Winter Precip: 3.43 inches

Average Seasonal Snowfall: 42.5 inches

Winter temperature and precipitation records date back to 1873, seasonal snowfall dates back to 1893 with average based on the years from 1966-95.


 

Intensity 1
(very weak)
Year Average Temp Average Precip Seasonal Snowfall
1875-76 26.2 6.22 no data
1889-90 24.8 5.50 no data
1946-47 22.3 4.70 35.0
1948-49 20.7 5.97 38.6
1963-64 21.2 2.73 32.1
1975-76 21.9 4.46 19.4
Average 22.9 3.71 31.3

Intensity 2
(weak)
Year Average Temp Average Precip Seasonal Snowfall
1873-74 21.6 4.55 no data
1917-18 12.3 1.89 47.3
1923-24 21.2 2.83 52.1
1932-33 22.4 4.82 37.1
1940-41 21.9 6.73 56.9
1943-44 26.1 3.18 29.5
1944-45 18.9 3.20 54.4
1951-52 20.3 3.42 67.5
1969-70 17.2 2.83 36.8
1992-93 19.7 6.42 58.7
1994-95 23.6 3.49 30.4
Average 20.5 3.44 42.8

Intensity 3
(moderate)
Year Average Temp Average Precip Seasonal Snowfall
1880-81 14.7 4.62 no data
1885-86 20.2 6.01 No data
1887-88 13.2 3.57 No data
1888-89 19.9 3.74 No data
1896-97 20.9 4.72 41.8
1900-01 19.7 2.01 43.2
1902-03 18.4 3.99 27.6
1905-06 22.7 5.40 40.3
1912-13 20.5 3.92 33.1
1914-15 19.1 3.29 44.7
1919-20 13.1 5.09 55.9
1929-30 20.7 2.69 44.1
1930-31 27.8 2.96 36.7
1939-40 21.7 1.38 38.4
1953-54 24.8 3.47 18.8
1965-66 19.2 5.77 20.0
1976-77 12.6 1.55 27.1
1986-87 26.0 2.50 37.8
1987-88 19.0 5.58 38.7
1991-92 26.0 8.79 64.1
Average 20.0 3.27 43.0

Intensity 4
(strong)
Year Average Temp Average Precip Seasonal Snowfall
1877-78 34.7 6.17 No data
1878-79 20.1 1.51 No data
1884-85 12.4 5.01 No data
1891-92 24.0 2.43 No data
1899-00 18.2 3.46 57.4
1911-12 13.9 6.35 47.1
1918-19 25.9 2.78 35.0
1925-26 20.1 4.73 54.5
1926-27 20.4 4.22 39.6
1941-42 24.0 3.93 37.1
1957-58 21.3 3.82 24.7
1958-59 13.4 3.52 78.3
1972-73 20.2 4.76 52.7
1973-74 18.7 3.70 35.0
1982-83 24.1 6.56 36.9
1983-84 16.9 4.68 29.4
Average 19.8 3.58 44.0

 


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