It sounds like you're describing a pack that mostly carries your personal needs and will be on your back to take care of you during NERT/CERT work.

How about a hydration pack (Camelbak, etc.) or a pack that is hydration-compatible? This way you could continue to work and drink without constantly stopping to open your pack.

They're probably providing or requiring you have this stuff already, but here's a few things that come to my mind:

- Good quality leather gloves.
- Small first aid kit.
- Lots of medical gloves.
- Lightsticks.
- Compass.
- Street map.
- Small GPS (maybe).
- Warm hat.
- Method of water purification (MP1 tabs, small filter, etc.)
- Backup knife / multi tool.
- Dust masks - N95 or similar.
- Safety glasses.
- Foam earplugs.
- Flagging tape / permanent marker.
- Chalk sticks.
- Spare batteries for your electronics (AA or AAA lithium).
- Waterproof notepad (Rite-in-the-Rain or similar) and pen.

Lived in SF for a couple of years and you're right, it can get cold. As the saying goes, "The coldest winter I ever spent was a summer in San Francisco." A good fleece would be perfect -- light and warm. Oh yeah, extra socks, too.