A period of above normal temperatures at the end of March and from April 6th to 9th produced snowmelt and strong within bank rises to minor flooding on the Trempealeau and Black Rivers during the first part of April. Some ice jamming played a part in the flood crest on the Trempealeau River. A couple days of heavy rains on the 12th and 13th produced strong within bank rises to minor flooding on the Turkey and Kickapoo Rivers from the 14th to the 17th. Spring snowmelt runoff plus the above normal April rains produced bank-full to minor flooding conditions on the Mississippi River between Lake City MN and Guttenberg IA during the second half of April.
Precipitation for April 2014 was above to much above normal, with the higher totals mostly across the southeast half of the HSA. Moderate to locally heavy rain and snow occurred across mainly the central and northwest parts of the HSA on the 3rd and 4th. Light to moderate rains fell across much of the HSA on the 7th. A strong two-part low brought moderate to heavy rains to mainly the central and southeast parts of the HSA on the 12th and 13th. Light snow fell at many locations on the 14th. A weak system brought light rain to mainly the northwest third of the HSA on the 16th into the 17th. A slow moving cold front brought light to moderate rain to much of the HSA from the 19th to the 21st. Another strong low brought widespread moderate to heavy rains to the HSA on the 24th. A large and slow moving surface and upper level low brought widespread moderate to locally heavy rains to much of the HSA from the 27th to the 29th, with light rains to end the month on the 30th.
Normal April rainfall ranges from around 2.75 inches across the north end of the HSA, to around 3.5 inches across the south end. April 2014 total ranged from 150 to 200 percent of normal in the drier areas to 200 to 250 percent of normal in the wetter areas. Most precipitation totals for April were 175 to 225 percent of normal. Extreme totals recorded for the month ranged from 4.06 inches at Medford in Taylor Co. WI and 4.40 inches at Owen in Clark Co. WI, to 8.08 inches at Fayette in Fayette Co. IA and 8.70 inches near Hillsboro in Vernon Co. WI. Snowfall for April was generally near normal across the southeast third of the HSA to above and much above normal across the northwest and north ends. Monthly totals were mostly 1 to 3 inches across the southeast third, up to 8 to 15 inches across the north-central WI portion of the HSA. Normal April snowfall ranges from 1.5 to 3 inches from south to north across the HSA. Snow totals for this month ranged from 75 to 125 percent of normal across the southeast end to 200 to 400 percent of normal across the northwest and far north ends of the HSA.
April 2014 temperatures averaged 37 to 46 degrees. This was 1.5 to 3 degrees below the normals. Temperatures were below to much below normal from the 1st to the 5th then near to above normal from the 6th to the 12th. Temperatures were again below to much below normal from the 13th to the 18th and above to much above normal for the 19th through 21st. The month ended with near and below normal temperatures from the 22nd to the 30th. Extremes for the month ranged from lows in the teens to middle 20s on the mornings of the 2nd and 5th, to highs in the 60s to lower 70s on the 19th and 21st.
Flows in the rivers and streams of the HSA were above normal during April. The above normal April rains finally eliminated the abnormally dry to moderate drought conditions that had lingered from the summer and autumn of 2013. The below normal temperatures and above normal rainfall during April delayed most spring fieldwork and planting activities, with much of this work 2 to 3 weeks behind normal at the end of the month.