A major snow storm hit Mauna Loa on February 27, 1990 and continued through March 1. The storm left 0.5-1.0 m drifts across the upper portions of the MLO road above the 3.0 km level. Several attempts to reach the observatory (even by 4-wheel drive vehicles) were unsuccessful until Tuesday, March 6, when Steve Ryan and Darryl Kuniyuki hiked in (about 2.5 km) and were able to check station conditions. The station facilities and instrumentation were in good condition and many observations had continued under CAMS* control throughout the storm isolation period. CAMS tapes had switched although chart rolls had run out, operating filters had run extra time, and moisture traps on the CO2 analyzers had frozen up. These were not unexpected occurrances. On Friday, March 9, a 4-wheel drive truck got within 100 m of the lower visitor parking area and the crew walked the rest of the way in. At this time, most of the remaining instruments were reset and restarted in a normal operational routine. On Monday, March 12, it was possible to drive to the observatory in the MLO station wagon, although it was necessary to use tire chains to get up the last hill above the lower parking area. Full operation of the MLO program was resumed on March 12. This storm was the most severe in the 34-year history of MLO. The "old timers" cannot remember a situation where snow blocked access to MLO for more than 2 consecutive days, compared to this storm's 1-2 weeks of inaccessibility. It is encouraging to note that the MLO operations survived this event in good shape with a high percentage of data recovery.
*CAMS is an acronym for Control And Monitoring System. This was the data acquisition system used for most of the projects at MLO at this time.
Hiking up the last leg to the observatory, March 6 1990 (above).
Steve Ryan in a waist high snow drift (top). Snow covered Mauna Loa Observatory in the background (bottom).