East Face of Mt Teewinot from Lupine Meadows. Snow line at 8,000 feet. 9.21.2019
The first of several storm systems impacted the Tetons during the first week of September. Since then, significant snow fall has continued above 10,000 feet. Expect to find much more challenging winter conditions on the Grand and other high peaks. If hiking or backpacking in the mountains it's that time of year to be prepared for much wetter and colder conditions. The days are getting shorter and the temperatures are falling. Be sure to pack plenty of extra layers and a headlamp.
The following link is a good write up on September weather events:
https://www.mountainweather.com/2019/09/summer-snowstorms/