Here is the text of the email I just sent to Donna Thompson at UW. Hoping she is the right contact. If someone passing that way has some warning chalk or something, might be a stopgap measure.
Assistant Director, Donna Thompson
email@example.com (206) 685-8552
I almost was severely injured, as was my seven year old son yesterday. We were proceeding north along the most direct route without stairs from the Montlake Bridge to the Burke Gilman trail. This route passes through the parking lot in front of Husky Stadium, which is newly constructed. It is the first time since it was constructed I have traveled this route. There is a new staircase that is blind to cyclists traveling north that was not there before this new construction. It is unsigned and there is little if any warning. I was able to yell stop to my son at the very last minute and thankfully he heard me and responded. I recall the cycling death in South Lake Union a few years ago when a bicyclist went down unsigned stairs near the WSECU offices. As a result at the point, a barrier was placed to prevent further cycling accidents. I recommend immediate placement of warning tape blocking these stairs, and then construction of some sort of barriers and signs to prevent cycling accidents here. I have attached a picture of the danger scene, taken from the north.