You're very daring and persistent to have continued to the summit in that weather - and going so late in the year.
For several years I had consistent luck visiting Whitney around the 3rd week of Sept and getting clear blue skies.
Then in 2007 it snowed heavily on the day of my permit. I did not even bother to leave home. I saw a trip report and photos of that day from someone else's hike that week. They went as far as trail camp and reported 3 ft drifts.
I tried again on 9/10/2008. Nice weather up until about 8:00 am when I reached Trail Camp. Then the clouds started rolling in.
By the time I was half way up the switchbacks it was raining sleet and close to zero visibility. The trail looked like your photo - covered white.
I turned around not far from Trail Crest not knowing how bad it might get, and not really enjoying the hike at that point.
I go to Whitney for the views, not just the challenge. If I can't see anything there is no point in hiking. But that is just me.
Here is my trip report of that hike..
http://www.mtsanjacinto.info/viewtopic. ... highlight=
congratulations on your successful struggle.