According to Barbara Russ (MMT staff) and Gary Schmidt (former director of the MMT), the mountain has been evacuated. Small groups were allowed up today wearing protective equipment to secure equipment away from windows and other vunerable spots. Because the fire is getting close, the fire crews have been moved out, as they could quickly get trapped on the mountain top if the fire comes through.
The MMT itself is likely safe from any fire, because it is located on a large rock far from trees (see some of my pictures from last September). However, many of the smaller telescopes and the astronomer's sleeping and eating quarters are in the forest and could be destroyed by the fire.
Yesterday it looked like it might rain, but the big clouds only produced wind, which made matters worse rather than better. It looks like there won't be any rain today, but tomorrow is looking quite promising. Here's hoping the Observatory and its neighbors living in Madera Canyon (also threatened by the fire) stay safe and secure until the rains come!