Tuesday, July 06, 2004 13:00 MST

Hello all,

We have 2 dozers cutting line from the north side of the Utility Area to the access road in the saddle just east of Peak 10,298. This line is to protect the Observatory's north and west side. All traffic other than essential fire traffic has been halted to the mountain. Currently MGIO is supplying water to the slurry batch plant just up Swift Trail. The retardant is batch mixed into dip tanks -- helicopters come by and pick up the retardant and make a drop on the fire as directed by the air attack crew (a "flying control tower"). I will send a couple of images following this message. As soon as we get a request from the site for water we will switch modes and supply water to the Observatory to feed the sprinkler system -- currently our 55,000 gallon tank is full.

At 1:10 PM today we have a hot dry atmosphere with winds (5 - 10 mph) from the north. This morning's fire maps are attached FYI.

We expect today to be difficult as the humidity drops and the Haines Index is projected to go to 6 from the period 1:00 PM to 5:00 PM today. The Index is a reasonable indicator of fire behavior. The Haines Index is described below:

Haines (1988) developed the Lower Atmosphere Stability Index, or Haines Index, for fire weather use. It is used to indicate the potential for wildfire growth by measuring the stability and dryness of the air over a fire. It is calculated by combining the stability and moisture content of the lower atmosphere into a number that correlates well with large fire growth. The stability term is determined by the temperature difference between two atmospheric layers; the moisture term is determined by the temperature and dew point difference. This index has been shown to be correlated with large fire growth on initiating and existing fires where surface winds do not dominate fire behavior.

Haines Index is computed from the morning (12Z) soundings from RAOB stations across North America.

The Haines Index can range between 2 and 6. The drier and more unstable the lower atmosphere is, the higher the index.

a.. 2 : Very Low Potential -- (Moist Stable Lower Atmosphere)
b.. 3 : Very Low Potential
c.. 4 : Low Potential
d.. 5 : Moderate Potential
e.. 6 : High Potential ------ (Dry Unstable Lower Atmosphere)

We will keep you informed of events this afternoon. I just talked with one of the division supervisors on site, Bob Kemp. He said to tell everyone "not to worry the site defenses are looking real good."

More later today...

John Ratje
 


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