A followup today from Jeanne Turner, who along with husband Mark shared first word of the Pigeon Point sinkhole last weekend:

SDOT arrived at 19th SW and Charleston on Pigeon Point this morning with a crew and equipment to fix a sinkhole that opened up Sunday afternoon. Dan Doyle of SDOT (a fellow West Seattleite) said the hole appears to be 18 inches to 2 feet deep. Today they will knock out the concrete and fill the hole with rock and gravel to stabilize the area. This will be covered with asphalt for a temporary fix until they can pour concrete. Because the area is relatively large, affecting four concrete slabs, SDOT will probably wait until spring to make the permanent fix.

Thanks for the update and photo!