Yes, you may want to give them a rinse in tank water today. this will remove any mulum build up that can rot in a long power cut.
when the power comes back on, run filters in a bucket of tank water before connecting to the tank again(or rinse agian).
do a water change after the power comes back on, not during the power cut.
ISSUES , 1.Temp dropping ,2. lack of O2 in tank , 3.lack of O2 in filter
1.Temp dropping, it all depend were the temp is now and how quickly it drops and what fish you have ??
for run of the mill com fish 16C I would start to be worryed.
2. lack of O2 in tank, this would only be a worry if you tank is over crowed.you will know you have a problem if you fish are gasping at the surface.
how many fish do you have in your tank and how long are they also what is the water surface area(dimentions, length left to right and depth front to back) of you tank.
3.lack of O2 in filter, I really don't know but if the bacteria cant breath they will start to dye and the anarobic (spelling ) bacteria will grow creating toxic water in you filter-hense why you need to rinse the filter before connecting to you tank.
hope this helps just a little.
p.s turn your filter off at the wall so it wont come on and pollute the tank before you rinse it.
An other ideas people ???