The heroic copter crew had responded to an Anne Arundel County crash and transported the injured parties to the Prince Georges County Hospital Center. They were departing when the helicopter struck a snow bank adjacent to the helipad. No injuries were reported.
Past problems with Medevac crashes have been discussed here in the past. See : http://www.maryland-law.com/blog/many-failures-cited-in-2008-maryland-medevac-helicopter-crash.cfm