Extreme cold warning

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An extreme cold warning is a weather warning issued by Environment and Climate Change Canada (ECCC) and by the United States' National Weather Service (NWS) to inform the public about active or imminent severe cold temperatures in their local region.

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As of April 8, 2014, ECCC replaced the "Wind Chill Warning" with an "Extreme Cold Warning." In the older system a wind chill warning for Southern Ontario and Atlantic Canada was issued when the wind chill dropped to -35. Thus a temperature of −37 °C (−35 °F) with no winds would not require a warning be issued. Under the new system the extreme cold warning is issued based on either the temperature or the wind chill being a certain value for at least two hours. The values range from −30 °C (−22 °F) in the warm temperates to −55 °C (−67 °F) in parts of the Arctic. [1] [2]

As of 1 October, 2024, the NWS replaced the "Wind Chill Warning" with the "Extreme Cold Warning." The standards governing issuance are set by local NWS offices. [3] [4]

Canada

An extreme cold warning is issued when the following temperatures are expected to last for at least two hours, which different regions have different criteria for: [2]

United States

In the United States an extreme cold warning was an experimental weather warning issued by the National Weather Service in North Dakota, South Dakota, and Minnesota. [5] The warning was issued if the temperature fell to −35 °F (−37 °C) or colder with a wind of less than 5 mph (8 km/h; 2 m/s). [6] It was an experimental advisory for when the air temperature was dangerously cold, but the wind was too little to warrant a Wind Chill Watch or Warning. [7]

The Extreme Cold Warning was used from January 10, 2011 to April 15, 2011. [8] It was discontinued beginning with the 2011-12 winter storm season. Only five Extreme Cold Warnings were issued in that period: one for Burleigh County, three for areas outside of the Bismarck–Mandan metropolitan area, and one for West Glacier, Montana [9]

In a partner webinar on October 30, 2018, the National Weather Service announced that based on survey feedback, the Extreme Cold Warning and the Wind Chill Warning will be consolidated into the Extreme Cold Warning, meaning that this product would once again be issued on a regular basis. This change was hinted to take effect sometime in 2021, accounting for NWS software upgrades. [10] [11] This was confirmed at the AMS 2024 meeting in January 2024.

In October 2024, the NWS officially implemented these changes to its wind chill and hard freeze warnings, watches, and advisories (WWAs) as part of its "Hazard Simplification initiative." The goal of these WWA name changes, per the NWS, is "simplifying a suite of cold weather forecast products to improve messaging of winter hazards and provide better decision support." The changes include: [12] [13]

Extreme Cold Consolidation and Renaming

Freeze Consolidation


Local NWS offices will still determine the standards governing the issuance of such WWAs.

Example

URGENT - WEATHER MESSAGE National Weather Service Missoula MT 237 PM MST Sun Mar 3 2019  MTZ002-003-007-043-041800- /O.NEW.KMSO.EC.W.0001.190304T0300Z-190304T1800Z/ West Glacier Region-Flathead/Mission Valleys- Butte/Blackfoot Region-Potomac/Seeley Lake Region- 237 PM MST Sun Mar 3 2019  ...EXTREME COLD WARNING IN EFFECT FROM 8 PM THIS EVENING TO 11 AM MST MONDAY...  The National Weather Service in Missoula has issued an Extreme Cold Warning, which is in effect from 8 PM this evening to 11 AM MST Monday.  * TEMPERATURES...15 to 30 below zero, with local areas down to 40   below zero.  * TIMING...Late this evening through mid morning Monday.  * IMPACTS...Local power outages and broken pipes are possible due   to the extreme cold.  PRECAUTIONARY/PREPAREDNESS ACTIONS...  An Extreme Cold Warning means that dangerously low temperatures are expected for a prolonged period of time. Frostbite and hypothermia are likely if exposed to these temperatures, so make sure a hat, facemask, and heavy gloves or mittens are available.  &&  $$

See also

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References

  1. ↑ Environment Canada. "Wind Chill Hazzards". Archived from the original on December 17, 2005.
  2. 1 2 Extreme Cold Warning
  3. ↑ Michael Musher, National Weather Service Public Affairs. "National Weather Service Revises Watch, Warning and Advisory Products". News Around NOAA. Archived from the original on 2024-10-07. Retrieved 2024-10-10.
  4. ↑ Blaise Keller. "Beyond the Barometer: Changes coming to wind chill alerts". Wisconsin State Journal. Archived from the original on 2024-10-08. Retrieved 2024-10-10.
  5. ↑ "National Weather Service Plans to Issue 'Extreme Cold Warnings'". Archived from the original on 2013-06-16.
  6. ↑ "NWS To Experiment With 'Extreme Cold' Warnings". 10 January 2011.
  7. ↑ "Experimental Cold Warning Feedback Needed".
  8. ↑ "NWS Tests Extreme Cold Warning". Archived from the original on 2013-06-09.
  9. ↑ "National Weather Service ditching 'extreme cold' warnings".
  10. ↑ "National Weather Service Public Information Statement PNS18-11" (PDF). Retrieved February 1, 2019.
  11. ↑ "Update on Winter Weather Initiatives Partner Webinar" (PDF). Retrieved February 1, 2019.
  12. ↑ Michael Musher, National Weather Service Public Affairs. "National Weather Service Revises Watch, Warning and Advisory Products". News Around NOAA. Archived from the original on 2024-10-07. Retrieved 2024-10-10.
  13. ↑ Blaise Keller. "Beyond the Barometer: Changes coming to wind chill alerts". Wisconsin State Journal. Archived from the original on 2024-10-08. Retrieved 2024-10-10.
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