Lifted from the YNP wilderness conditions page 06/05/17. I'll only include what we generally recommend as "early season/lower elevation" routes. Shaping up like an all bets are off start to the season this year though.
Here's the actual link:
https://www.nps.gov/yose/planyourvisit/wildcond.htmParaphrasing what the report states very clearly with regards to "what should I bring?"-
It's not what you carry in your pack as much as it's about what you carry in your head. And you better be really good at it...
Hetch Hetchy Beehive Meadows, Laurel Lake, Wapama Falls Trails at low elevations are clear of snow with the exception of a 1 mile section of trail on Mt Gibson between Lake Vernon and Rancheria Falls. Trails are flooded and wet throughout. Wapama Falls footbridges may be covered by the waterfall as flow increases with warmer temperatures and melting snow. People crossing these footbridges do so at their own risk. It is not advised to cross Frog Creek at this time. Snow coverage starts on Moraine Ridge when dropping into Jack Main Canyon.
Valley Rim Lehamite Creek, North Dome, Taft Point, Sentinel Dome Water crossings are tricky with high and swift moving water. On the north rim, Tamarack and Wildcat Creeks are both flowing fast. Ribbon and Lehamite Creeks on the east side of the rim are both water heavy as well. Snow is still abundant in the forested areas along the rim, including Ribbon Meadow and Eagle Peak Meadows. The trail section of trail north of Indian Rock and North Dome has 100% snow cover. On the south rim, there is 75% snow coverage on the Pohono Trail from Glacier Point between Taft Point and Dewey Point. Glacier Point, itself, is mostly free of snow.
Glacier Point Rd Ostrander Lake, Illilouette Creek The trail to Ostrander Lake is clear until the last mile and then is 100% covered with depths of 5 ft. Trail to Mono Meadow is 50% snow covered for the first mile. Mono Meadows are completely flooded. Creek crossing just after Mono Meadows is high and hazardous. Illilouette Creek is impassable at Mono Meadow junction. Hikers will need to go to the panorama trail and use the bridge there to cross Illilouette Creek.
South End Chinualna Creek The trail to Chinualna Falls is clear. Crossing the main stem of Chilnualna Creek to the south is approximately 4 ft deep and not recommened. Once across, patches of snow begin to grow as elevation is gained hitting 100% snowpack around 8,500 feet.