It seems to have been going on forever; the combination of rain and ash falling to the streets of the city. With such a long period of time, many have found that they can and should go about their "daily business" as if it weren't raining.
That's why it might feel so sudden to one outside, suddenly no longer hearing the soft pitter-patter of raindrops and seeing on the ash fall in silence like snow. It's somewhat relieving that the rain has stopped-there are large puddles and slightly flooded streets in the lower parts of the city-however that ash hasn't come to a stop, for whatever reason. It gives you a right to be nervous, and nervous/cautious/suspicious (whatever reaction your character would take) they should be. A look at the map after so long shows that the red zones have not retreated back to their respected territories. In this case, it seems the yellow is starting to crawl its way forward into the few safe "green" zones the city has.
The only thing worse than all this happening at this moment is the unknown that you'll find once those yellow zones engulf all the green.
OOC!INFO Environment change! Currently 75% of the red zones on the map have edged forward over the yellow areas. The yellow areas on the map are starting to cover green zones and have consumed about 15% so far.