For all the reasons cited above, definitely get on the phone WHILE in line, and definitely consider going back out thru security to the ticket counters if everyone's heading for lines at gates...and, from an experience I had, I'd say even if the city you're stranded in is the hub of another airline, call THAT airline.... Really paid off for me once: Was to fly coach NWA/KLM STL/MEM/AMS/ACC. Bad storms at several midwestern airports were cancelling and delaying many flights. We went back out thru security to the NWA ticket counter. While in line, noting that STL is/was an AA hub, called AA reservations and played connect the dots for the hour and a half we stood in line. The only thing they had open were First Class to east coast US, Business to LHR, and First from LHR down to ACC. About then, we were at the counter, the NWA agent told us what we already knew, that there was nothing on NWA he could put us on for a couple of days, we told him that AA had a few openings in First, and so with the AA res. rep. still on the line we handed the agent the phone to get the flight info.etc. & we had our AA First/Bus./First tix to Africa at no extra charge.
And, rec'd miles for the flight in both airline accounts!! (NWA and AA). Tried to do the honest thing, called both airlines and both said that it was okay and not uncommon in situations like that!

(sidebar: at church the day before, my 6'6" self was not thrilled about the 22 hour flight in coach and asked my group to pray for a first class upgrade!)