The Fog Log Conclusion: Seven Dry Days

Moon and contrail over Sutro Forest

Today was the last day of the Fog Log, keeping track of that crucial period, “September-November, when dry, high-intensity winds blowing from the north-east combine with high air temperatures and low humidity,” according to the UCSF letter.

Here are the results: In the three months, the longest stretch the forest was without either fog or rain was ONLY 7 DAYS.

Once a week is about how often most people water their potted plants.

There were no dry hot winds from the northeast (or anywhere else).



For three months, from September through November, we updated a daily Fog Log. We wanted to know, between the end of summer (and fog) and the beginning of winter (and rain), was there enough dryness to raise fire risk? We kept track not only of the fog and rain, but also looked out for the “dry hot winds” blowing “from the Northeast” that the UCSF letter also mentioned.

At no time was the forest dry. On every visit, even at the end of a week-long dry period, the forest was damp. The only dry areas were where it had been opened out – the native garden and some areas on the trails. There were no dry hot north-easterly winds.

Native Garden Nov-end 09

In fact, by November end, there was green grass even in the driest spot on the mountain: The Native Garden.

Here are links to the daily fog logs, by month:

September had only 7 days that were fogless. Dry streak, 2.

October had 14 fogless days; Dry streak, 7 days.

November had 24 fogless days; Dry streak, 6 days.

(ETA: The fog came in Dec 1 evening.)

This entry was posted in Sutro Forest "Fire Risk", UCSF and tagged , , , , , . Bookmark the permalink.