The area of Vancouver is 113.1 square km
Source:
http://www.city.vancouver.bc.ca/ctyclerk/info_depts_boards/statistics.html.
Raindrop size:
raindrop is about 1 cubic mm.
Source:
http://www.gi.alaska.edu/ScienceForum/ASF2/236.html
http://wwwga.usgs.gov/edu/raindropsizes.html.
113 * 106 * 106 * 170mm which is about 1016 = 10000000000000000