My best guess is that 16ENA was heading down to 19 to cover or was already there, depending on how fast the second was struck.
Responses in Calgary (and outside it, for that matter) are decided by closest unit of a given type. On the 2nd alarm, the closest two engines, one aerial, and #23AL will be sent. Quints are considered engines to the computer and to CFD - they don't want them dispatched any other way. And 30 doesn't have their quint yet, anyway.
16A is the big Bronto, which was apparently special-called on the 2nd as mentioned above. When you want to move a lot of water fast from on high, it's the way to go. Especially considering the spare 14A is using right now is, if they haven't changed since Sunday night, a POS (IMO) from 1988.