Changing Seasons Brings Spring Weather and Construction at MSP

Spring has finally sprung in Minnesota, and along with the warmer weather comes seasonal changes to flight patterns, acoustics, and construction projects at Minneapolis-St. Paul International Airport (MSP).

Spring, as defined by the months of March, April, and May, is the windiest season of the year in Minnesota. MSP experiences average daily wind speeds in excess of 9 mph throughout all three months. Prevailing winds are predominantly out of the north/northwest from March through early May, then shift to predominately out of the south/southeast for the remainder of May.

This strong and shifting springtime wind pattern at MSP influences flight operations and sound exposure for nearby residents. Air Traffic Controllers at MSP use runways for takeoffs and landings based on wind direction, weather conditions, and air traffic demand. Aircraft are typically directed to depart and arrive on MSP's parallel runways oriented to the northwest (30L and 30R) and southeast (12L and 12R). With strong and shifting winds the runways that are used for takeoffs and landings vary and people living around the airport may notice this seasonal variation this time of year.

In addition to flight operations, spring weather may impact aircraft noise. Windy conditions generally cause sound waves to bend and move in the direction the wind flows, dispersing aircraft noise over a wider area and causing fluctuations in decibel levels. Cloud coverage, depending on thickness, can deflect or rebound aircraft noise back toward the ground. Temperature inversions, where air near the ground is cooler than air at altitude, usually occur overnight due to heat absorption by soil, cooling lake effects, and warm upper air jet streams. Inversions cause wind shear and a sudden difference in air density, usually a few hundred feet above the ground, which can deflect noise back toward the ground in a similar manner to clouds. Finally, warmer temperatures mean sparser air molecules and less efficient aircraft performance, leading to the requirement for longer takeoff runs, slower climb rates, and higher engine power levels. 

Spring also marks the start of many necessary construction projects at MSP. Airfield infrastructure (i.e., runways, taxiways, aircraft parking surfaces, etc.) regularly requires construction and maintenance to ensure the safe movement of aircraft. Construction projects at MSP may impact typical runway use by closing one or more runways at MSP temporarily, even when the activity is not occurring on the runway. Additionally, construction activities can impact how Air Traffic Controllers assign aircraft to open runways. Currently, airside electrical and roof replacement construction requiring periodic nighttime crane operations and temporary nighttime closures of Runway 12L/30R that began at the end of April and will continue through the middle of May, during the period of 11 P.M. through 5:00 A.M. Residents may expect additional departures or arrivals to Runways 17/35 or 4/22 during those time periods. Information about runway closures of 30 minutes or longer at MSP is available at: www.metroairports.org/msp-runway-closures. Anyone with questions about runway closures due to maintenance and/or construction may call the Metropolitan Airports Commission's Community Relations Office at 612-726-9411.