You can read summary articles of the annual Eastern Snow & Avalanche Workshop ("ESAW"), typically held on the first Saturday in November, near Mount Washington.
You can also download Jonathan's 2014 airbag presentation and even listen to the audio.
(Jonathan also presented at the 2012 ESAW, but no need to review that presentation, since the topic was ... this avalanche course!)
An avy-related blog [no longer updated though] is intended as a companion to this course, often highlighting recent incidents.
For the scientifically inclined, try The Avalanche Handbook (by David McClung and Peter Schaerer now in 3rd edition), which is a much more advanced scientific discussion, although far beyond the level of this course. (And you can even take an exam on it too!)
Similarly beyond the scope of this course, but perhaps of interest to the technically oriented, the American Avalanche Association's Snow, Weather, and Avalanches: Observational Guidelines for Avalanche Programs in the United States is available in digital format.
Also for the technically oriented, if you want to learn even more about mountain weather, then this aptly named book is tightly focused on exactly that topic.
Definitely subscribe to (and browse the archives of) The Avalanche Review, the publication of the American Avalanche Association, which also maintains an on-line library.