MOHAVE 2009, or “How Dry is the Atmosphere in Wrightwood?”
Well, just check this picture and you will have an idea right away…
Ironically, the “Sheep Fire” which started Saturday October 3rd, 2009 in Lytle Creek Canyon, propagated up the mountain 10 miles farther within 12 hours in an average ambient relative humidity of 45% and near-freezing temperatures! The top of Lone Pine Canyon, where the San Bernardino County Fire fighters successfully stopped the fire (bravo!), is a few feet from the first houses on the eastern edge of the town of Wrightwood.
What a better start for a campaign called MOHAVE (Measurements Of Humidity in the Atmosphere and Validation Experiments), which objective among others is to measure water vapor from the ground to the mesopause. It is therefore with great stress that I saw myself and family evacuating our home at 3 am Sunday morning (just 5 hours after coming back from a business trip to Europe), and seeking refuge at the JPL Table Mountain Facility. Once in safe place, the question that came up at the time was “should I stay or should I go?” Considering the amount of work I inflicted myself to stay on top of the campaign planning, the answer was trivial: I stay. Besides, the view from the observatory towards the fire was unbeatable, and allowed us to monitor the proximity of the flames to our homes.
During the following 3-day retreat, I managed to catch up some needed sleep, and sadly found out that the NASA GSFC lidar trailers and staffs expected to arrive on-site Monday and Tuesday for the campaign would never make it on time due to the massive road blocks the fire had prompted. Fortunately, the roads re-opened Tuesday mid-day, and by Wednesday morning all three lidar trailers were in place, just one day late, and “almost” ready for our upcoming intercomparison campaign.
In short, like if the desert vegetation at Table Mountain was not enough, this wildfire just reminded us how dry the area is. There is no question that our upcoming MOHAVE observations will very likely reflect the typical conditions of the descending branch of the Hadley circulation!