I spoke with Lisa this afternoon. It is quite cold and getting colder. It makes us appreciate having a toilet with a slight leak in the flapper valve; it keeps enough water flowing that the pipes probably won't freeze in the house. In the trailer, it takes the furnace running flat-out to keep the temperature at 18°C. Lisa says she's okay, though, with plenty of supplies.
Now I must try to get to bed early so I can be up at 3:30 AM to pack out of the hotel room and head to the airport. Upon reflection, I might have been better served by staying tonight only in a hotel nearer to SFO, particularly one of those with a park-and-stay package.