27 Albuquerque International Balloon Fiesta 2022 Media Guide THE SCIENCE OF THE “ALBUQUERQUE BOX” This wind pattern for which the Albuquerque area is well known and occurs under stable conditions during the fall season when no strong weather systems are affecting the area. On days when the “box” occurs, it dissipates by mid- morning as the sun heats the ground, resulting in thermal turbulence which mixes the separate layers of air and eliminating the low-level inversion. During the nighttime hours, the air near the ground surface is cooled by the process of radiational cooling. This process is most efficient with clear skies, low humidity, and light wind. Cooler, and therefore denser air flows downslope to lower elevations along arroyos and river valleys. The cool air that flows through the Rio Grande valley is shallow (generally no more than a few hundred feet in depth). During the early morning hours this air flows southward down the valley from higher to lower elevation much as any fluid flows downhill. A north wind generally less than 10 mph results in the middle Rio Grande Valley. The stable “river of air” occurs below a temperature inversion which separates it from warmer, less dense air above the inversion, just as vinegar is separated from oil by differences in density. The wind direction in the air mass above the shallow inversion can be different than that below the inversion. In an “ideal” box pattern, the wind blows in exactly the opposite direction with a north wind at the surface and a south wind above the surface. A skillful pilot can bring a balloon back to near the point of takeoff by changing altitudes to ride wind currents in different directions. Upon takeoff the pilot first heads south towards downtown, then ascends higher where the winds then take the balloon back north towards Balloon Fiesta Park. BALLOON FIESTA WEATHER