San Francisco residents knew they were in for it when it was announced that schools would be closed for the first-ever rain day. Thursday's storm didn't disappoint. As many as 150,000 residents and office workers experienced a power outage in downtown San Francisco, prompting the closure of the BART station at Montgomery. Buses were left inoperable on the street, and the city's iconic cable car system was shut down. 

Meanwhile commuters driving down to Silicon Valley via Highway 280 faced heavy floods, creating even heavier traffic. And business travelers were also affected, as over 200 flights were cancelled or delayed at San Francisco International.

In a city where "extreme weather" usually means thick fog, the monsoon-level precipitation caused a flurry of chaos, and local businesses had to improvise to keep a productive workday. Salesforce CEO Marc Benioff told all Bay Area employees to work from home and run their business on their phones in order to be safe. Google headquarters in Mountain View created a storm preparation area where employees could store their inflatable rafts.

Other startups encouraged being productive even in the dark. DocuSign VP of demand generation Meagen Eisenberg took to Twitter to remind customers that DocuSign can be used on mobile anywhere, anytime -- even when the electricity is out. Similarly, could platform Financial Force tweeted that with their mobile solutions not even big storms are valid excuse to skip work. 

Meanwhile, the Google Express delivery service got high marks for being relatively on time despite the circumstances. Uber was not as reliable, with surge pricing going up as high as 3.8 times the normal fare. For commuters who braved the storm in their cars, there was some good news: Parking meters were not enforced. Finally, a silver lining.