<p>So I have a teacher that taught me computer science in grade 10 and was our supervisor of our programming club grade 10-11. He’s been offering to write me a reference letter since grade 10 and continued to remind me up until this summer, as I was both a great student and a passionate member of the club (I’m actually now the head of the club). So we had things all sorted out, except he decided to take a year off teaching, and he’s somewhere in Europe right now. I emailed him all the info he would need for a rec, and suddenly he disappeared. He hasn’t replied to email from me or faculty/friends in 3 weeks, and the school can’t provide a phone number or any other method of contact.</p>
<p>Good part is, he was just writing a supplemental reference letter for me. Bad part is, I’m interest in comp sci at Stanford (SCEA), and this would be a crucial reference. 
I guess my question is, is this a big deal, missing out on a (really good) supplemental rec? Does the rec have to be in by the EA deadline? or can it be after? (which might give me a glimmer of hope)</p>