As of COB on March 14th after many hours of emailing and calling parents, all in-country JETs who either processed or departed through Denver have been accounted for. We had several people in the Tohoku region, some of whom have been displaced due to the current situation, but they are all doing OK.
If you are looking for an in-country JET, CLAIR NY has a list of US and Canadian JETs who have thus far been accounted for. The list continues to grow, so please keep checking back if you don’t see the name of the person you’re looking for.
Other online resources that have come into play with connecting people are Facebook and Twitter. There are several Facebook pages set up to connect people- some general and some broken down by prefecture.