Minneapolis – Saint Paul International Airport (MSP)

Winter Storm with strong winds and lightning
Thu 4/11/2019


From April 10-12, a strong winter storm produced a total of 10″ of snowfall at MSP. On April 11, this storm was paired with very strong winds of up to 50 mph and lightning.

Thanks to ClimaCell’s hyperlocal and accurate weather forecasts, a large airline was able to operate during periods of lower wind speeds, while taking the necessary and appropriate precautions to proactively suspend deicing during the high risk timeframes when winds were too strong. Similarly, they responded to the lightning risk appropriately and closed the ramps at the right time.


ClimaCell correctly predicted not only the type, timing, and amount of precipitation, but was also the only one to anticipate strong winds and cloud-to-ground lightning at the times they occurred.

Micro Decision

When wind speeds (including gusts) exceed 44 mph, this major airline has the policy to lower deicing booms and cease deicing until wind speeds decrease. Further, it closes the ramps when there is a cloud-to-ground lightning risk. Knowing about periods of lower wind speeds and the duration of lightning concerns allow this airline to continue operating and keep employees and equipment safe.

Macro Impact

ClimaCell’s instant messaging and alerting enabled the ACC to proactively suspend deicing only for short durations which materialized as above threshold. There are 2 scenarios how the ACC would have handled high winds without ClimaCell:

  1. In strict adherence to the ground operations manual, forecasted winds exceeding 44 mph at some point between 5:20am — 4:00pm, would have caused the ACC to suspend all deicing operations; thus resulting in cancellations or significant additional delays to over 68 flights (a typical operation during this timeframe would have impacted ~190 flights). The impact is estimated to be between $700K and $2M — for an individual event at a location prone to winter storms.
  2. The ACC could have waited for winds gusts to appear to increase in an attempt to then suspend deicing prior to reaching 44 mph. However, considering the nature of wind gusts, they would have surpassed the threshold far more often than the luck of guessing accurately.

Further, without ClimaCell the ACC would have had to close the ramps for longer than necessary, as its other forecasts issued the same alerts for dangerous cloud-to-ground lightning and for less relevant cloud-to-cloud lightning.

Traditional forecast

Traditional weather forecasts predicted precipitation, but picked up late on strong winds and lightning risk, and couldn’t specify the timing. When contacted because of ClimaCell’s forecast, another weather service said: “I can’t rule out high winds. In the next 9 hour period, strong winds are unlikely but you might see some.”

ClimaCell forecast

ClimaCell provided consistent forecasts in the 36 hours prior to the storm. It correctly predicted strong winds and wind gusts mainly Thu morning into early Thu afternoon, and the potential of thunderstorms.

April 9 (Tue)

  • 05:00am: Storm total snowfall of 10-15″ expected.
  • 1:00pm: On Thu, mixed snow/ice pellets mainly in the morning. Winds gradually increase through Wed, peaking Thu morning at 25-31 mph sustained, with gusts to 46 mph.

April 10 (Wed)

  • 05:00am: Gusts to 40 mph by 6am Thu.
  • 1:00pm: Winds at 23-29 mph, gusting to 46 mph on Thu through 1pm, then steadily easing.

April 11 (Thu)

  • 05:00am: Winds increase to 29-40 mph with gusts to 58 mph after 9am, then decrease to 20-29 mph with gusts up to 40 mph after 3pm, and to 8-17 mph with gusts up to 26 mph after 7pm.

Alarms (April 11, Thu): ClimaCell Weather Hazard

  • 4:20am: Wind gusts increase (58 mph after 9am).
  • 6:50am: A developing line of thunderstorms with wind gusts to 58 mph threatens MSP by 8am.
  • 11:17am: After 1pm, elevated risk of thunderstorms.
  • 2:27pm: Threat for isolated lightning within 10 miles.
  • 4:00pm: The main axis of showers and thunderstorms has now pushed north of MSP, with lightning concerns having ended. The threat for wind gusts >44 mph has also decreased significantly.

Excerpt of the Irregular Operations Report,
MSP, April 11, 2019

Sustained wind (blue) and wind gust (red) at
MSP, April 10-12