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*              HydroClim Minnesota - January, 2000              *
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* A monthly electronic newsletter summarizing Minnesota climate * 
* conditions and the resulting impact on water resources.       *
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* Distributed on the Wednesday following the first Sunday of    *
* each month.                                                   *
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* State Climatology Office - DNR Waters                         *                    
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* compiled 1/5/99                                               *
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WHAT HAS HAPPENED:

- most Minnesota communities received less than one half inch of precipitation during December. This is approximately one half inch to one inch below the historical average.
(see http://climate.umn.edu/cawap/monsum/monsum.htm)
- for the period October 1 - December 31, precipitation across most of Minnesota was two to three inches below the historical average.
- with the exception of southwestern Minnesota, the autumn and early winter dry spell comes on the heels of a very wet growing season. In balance, most of Minnesota was at or above normal for annual precipitation to date. 1999 annual precipitation maps will be available in late January. 
(see http://climate.umn.edu/doc/annual_pre_maps.htm)
- November was extraordinarily warm including two of Minnesota's warmest November days ever. In spite of a mid-month cold snap, December was also unusually mild. Both months finished seven to ten degrees above the historical average.
(see http://climate.umn.edu/cawap/monsum/monsum.htm)
- water resources normally rejuvenated during the autumn recharge remain quite dry. The dry autumn weather created favorable agricultural field working and grain drying conditions. The dry weather led to some autumn grass fires and increased awareness of forest fire danger. 

WHERE WE STAND NOW:

- the National Drought Mitigation Center categorizes most of Minnesota to be climatologically neutral. However, southwestern Minnesota falls in their "D2" category ("Severe Drought - crop or pasture losses likely; fire risk very high; water shortages common; water restrictions imposed"). The NDMC index is a blend of science and subjectivity where intensity categories are based on six key indicators and numerous supplementary indicators.
(see http://enso.unl.edu/monitor/monitor.html)
- the Palmer Drought Index places southwestern Minnesota in the moderate drought category, near normal elsewhere. The Palmer Drought Index is used for assessing long-term meteorological conditions.
(see http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif
- surface soil moisture is dry in nearly all locations. Dry conditions extend throughout the rooting zone in the southwest, near average to moist middle and lower layers elsewhere.
(see http://www.nass.usda.gov/mn/cropwthr.htm, http://climate.umn.edu/img/soil_moisture/lambsm11.gif, http://climate.umn.edu/img/soil_moisture/wassm12.gif)
- stream flow varies greatly across Minnesota.  Many streams in the northwest remain above the 90th percentile, whereas some stream flows in southwestern and east central Minnesota fall below the 10th percentile.
(see http://water.usgs.gov/cgi-bin/daily_flow?mn)
- snow depths across most of Minnesota are low as of this writing. Reported snow depths were generally less than four inches. Early January snows increased snow depths to roughly six inches in far southeastern Minnesota. Most of Minnesota ranks below the 20th percentile for snow depth, with many areas falling below the 5th percentile.
(see http://climate.umn.edu/doc/snowmap.htm)
- despite the sparse snow cover, frost depths are seasonally shallow due to above normal temperatures. Reported frost depths range from 8 to 18 inches.
(see ftp://ftp.mvp-wc.usace.army.mil/pub/bulletins/Snow_Ice_Frost)

FUTURE PROSPECTS:

- the winter outlook from the Climate Prediction Center shows a tilt towards above normal precipitation for January, and for January through March. The temperature outlooks call for near normal conditions.
(see http://www.cpc.ncep.noaa.gov)
- dry autumns do not necessarily portend dry winters and springs. When the Twin Cities' driest October through December periods were examined, the January through April precipitation totals that followed included the typical distribution of dry, wet, and average conditions.
- from agricultural climatologist Mark Seeley ... "Drought which begins in the fall season is typically less consequential than drought which begins in the winter, spring or summer.  Winter drought can cause desiccation of plants, and winter injury to pasture grasses, winter wheat and alfalfa.  Spring drought can cause delayed crop planting and emergence and/or significant soil loss from wind erosion, while summer drought can stunt plants, cause drastically reduced crop yields, and very low river flows that present navigation problems. The current dry conditions can yet be mitigated in two ways: (1) by heavy overwinter snow cover which will infiltrate into the dry soil layers with each thaw cycle of the late winter; or (2) by early spring precipitation which will recharge the depleted surface layers of the seedbed and perhaps bridge the dry layers of the root zone with the more saturated layers of soil below.  Thus, though the current lack of soil moisture in parts of Minnesota is of concern, there are still a number of ways that the soil could be recharged sufficiently for the year 2000 crop season."
- foresters are concerned about the potential for a major burn in the BWCA. Many trees blown down by the July storm rest on their larger branches, keeping most of the heavier fuel off the ground. This architecture, plus a lack of shade, creates an excellent drying condition. A modest dry spell in future growing seasons will lead to high forest fire danger in that area. 

NOTES FROM THE FIELD:

- Spicer:      many Type 3 and Type 4 wetlands completely dry
               some lakes one foot below October averages
               some lakes at lowest levels since late-1980's drought
- Hutchinson:  some wetlands completely dry
               topsoil dry as dust, concern for soil erosion

UPCOMING DATES OF NOTE:

- January 26, Interagency Flood Planning Meeting, Corps of Engineers - St. Paul
- January 20, Climate Prediction Center releases newest 30/90 day outlooks

WEB SITES FEATURED IN THIS EDITION:

http://climate.umn.edu - Minnesota Climatology Working Group
http://enso.unl.edu - National Drought Mitigation Center
http://www.nass.usda.gov/mn - Minnesota Agricultural Statistics Service 
http://mn.water.usgs.gov - U.S. Geological Survey in Minnesota
http://www.mvp-wc.usace.army.mil - U.S. Army Corps of Engineers - St. Paul District
http://www.cpc.ncep.noaa.gov - Climate Prediction Center

ACKNOWLEDGEMENTS:
Robb Collett, DNR Waters Area Hydrologist - Hutchinson
Skip Wright, DNR Waters Area Hydrologist - Spicer
Dr. Mark Seeley, University of Minnesota Extension Meteorologist/Climatologist

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Last modified: January 5, 2000