In a game I just played on a separate account, whenever Jarvan got snared by a Lux E, he was repeatedly able to dash out of it. He was also able to ignore Morgana's snare in the same way. This seems unexpected, because snares are supposed to stop movement.
The Deckowner1 voteswhen a champion is in mid dash no cc can stop it other than knock up/displacement.
TheyCallMeRach2 votesit wasn't mid dash, the snares landed before the Q went down
The Governer1 votesWell if he presses Q to the flag before the snare lands he will still be able to dash despite being snared.
No flash no life1 votesThat's how his skills work. He can e + q to move even when snared and it's been that way for a long time. True, snare is supposed to prevent all forms of movement, but 
and 
have already broken that logic.
The Governer1 votesYou can finish your dash during snare if you successfully input the dash command before the snare lands. You are not supposed to dash if you do not input the command before the snare lands.
In case you are wondering, Kalista's R and Tahm Kench's W are not dashes.