National Weather Service United States Department of Commerce


The Cold Weather Advisory for Newborn Livestock (CANL) system was created by the National Weather Service Forecast Office at Glasgow, Montana, Dr. Larry Kalkstein at the University of Miami and Dr. Katrina Frank at the University of Delaware. Dr. Kalkstein is one of the leading researchers on weather effects on humans (biometeorology), and Dr. Frank has a background in animal sciences and climatology (bioclimatologist). The system is designed to indicate weather conditions dangerous to newborn livestock. The criteria for this system were derived from interviews with Montana ranchers and from published scientific research on animal health.

We are targeting those livestock that are less than 24-hours old because these animals are least able to regulate their body temperature and therefore most susceptible to the cold. Also, after several hours, producers may have had a chance to get to the animals, dry them off, and provide shelter as needed.



Based on our research and feedback from the ranching community, the following were identified as hazardous weather elements that increased risk of problems or death to exposed newborns:


  • Wind Chill
  • Rain or Wet Snow
  • High Humidity
  • Any combination of these elements (such as wind chill and rain) are particularly dangerous

The criteria used to generate the forecasts from the tab above is seen below:

  • NONE: Wind Chill above 41 degrees
  • SLIGHT: Wind Chill less than 41 degrees for 2 or more hours
  • MILD: Wind Chill less than 32 degrees for 2 or more hours
  • MODERATE: Wind Chill less than 0 degrees for 2 or more hours or Wind Chill less than 36 degrees and .02" precipitation
  • SEVERE: Wind Chill of -9 degrees or colder for two or more hours, or wind chill of less than 34 degrees and .05" of precipitation
  • EXTREME: Wind Chill of -18 or colder for two or more hours, or wind chill less than 32 degrees and .1" of precipitation
  • For sunny conditions (Cloud cover less than 40%), reduce SLIGHT-EXTREME by one category
  • For humid conditions (Minimum relative humidity's remaining above 95%), increase MOD-SEVERE by one category
  • For dry snow conditions (Maximum temperature remains less than 26F), double the precipitation thresholds for MOD-EXTREME