With gas prices hovering in the low-$4 range, with premium fuel regularly coming in at cents away from $5, prepare yourself for more crowded BART commutes and sidewalks crisscrossed with electric scooters in the days to come.

In San Francisco, the average gas price now sits at $4.35 a gallon, according to the AAA—who not only will help you change a flat tire but also track and chart your state's gas prices. Despite the national price average per gallon still hovering at around $2.65 per gallon, the Golden State's figure is well over $4, as of this article’s publishing.

Just a month ago Oakland, San Jose, and San Francisco gas prices averaged between $3.50 and $3.70 a gallon; the $0.60-plus price hike was quick and swift, which threw many a driving San Franciscan into a tizzy.

“It’s ridiculous that gas is almost $5 a gallon,” said 27-year-old Mike Sellers to the Chronicle, who was filling up near a downtown SF Shell station...where prices were as high as $4.89, earlier this week.

“I’m just filling up the bare minimum,” he added, before saying that he intends to top-off his tank closer to his East Bay home where prices were roughly $0.75 per gallon cheaper.

This, too, marks a five-year high in gas prices in parts of the country. According to KRON 4, the drastic (and rapid) price spike was due to outages at several refineries responsible for supplying gas to California, Oregon, and other states along the West Coast.

While it's not uncommon for refineries to completely cease production during certain times of the year—like when they switch between seasonal blends of gasoline or start production cycles for cleaner-burning fuels, which are also more costly to produce—these specific production hiccups, however, were unexpected; reports have been made that some of these facilities are now back to operating at full tilt, allegedly.

Couple that happenstance scenario with California’s well-known carbon emissions and fossil fuel taxes, and it’s little wonder why Bay Area loci are cringing at the pump.

Gas prices are expected to settle down a bit in November, as more refiners come back on board, and blends are officially switched over and transported to West Coast filling stations.

Image: Bev Sykes, via Flickr