Not to be forgotten about the uncommonly heavy rainfall that soaked the state this week is that it might no longer be so uncommon.

At issue here was what the National Weather Service called a “kona low,” a meteorological condition related to the same atmospheric rivers of moisture that dump rain on the Pacific Northwest, known as the Pineapple Express, and can bring deluges to Hawaii as well.

Whatever the exact mechanism that brought the slow-moving rainclouds here, we’ve all been told now, in the age of climate change, to expect that they will continue, and with heightened intensity.

The biggest surprise seems to have been the vulnerability of urban Honolulu infrastructure. While it’s not the only example in memory — overwhelming storm water in 2006 led to the diversion of raw sewage into the Ala Wai Canal when a sewer main cracked — Oahu often seems to dodge the bullet of weather disasters. People tend to forget what’s at stake.

Honolulu’s luck ran out this time. As of midday on Wednesday, about 180 reports of residential damage have come in, ranging from minor repairs needed to accounts of total destruction, mostly between Pearl City and East Oahu, according to city officials.

It is good that the city began promptly collecting this information through self-reporting tools posted online (honolulu.gov/homedamage for residential, honolulu.gov/businessdamage for businesses). That’s because Mayor Rick Blangiardi waived all permit fees arising from emergency work so that assessments and repairs can start immediately.

The Hawaii Emergency Management Agency issued some critical advice to residents in doing the recommended documentation for insurance purposes: Don’t wade through floodwater that may be concealing debris or be contaminated or produce an electrical shock.

The kona low broke a single-day rainfall record on Monday, when Honolulu was drenched with 7.92 inches, making it the wettest December day.

The only positive that comes from any of this is that extreme weather reveals a community’s weak spots, enabling an assessment and prioritization of what fixes to make first.

Some of it became evident when the lights went out in downtown Honolulu. Three Hawaiian Electric Co. transformers had failed due to flooding in the Iwilei substation. Damage to high-voltage cable had to be repaired and spliced.

The protective barriers at the century-old substation were insufficient. As much as the power company should review the resilience of such facilities, the outage also underscored the need for businesses, schools and other institutions to consider their own stormproofing and backups.

Hospitals and nursing homes generally do have built-in redundancies, but any location with crucial electrical systems should consider having generators on hand and maintained, as well.

One of the characteristics of this storm that set it apart was its statewide impact. The storm came from the south and swept the island chain, reserving some of its particular fury for Maui. The reports of blizzard conditions on the Big Island’s summits surprised the kamaaina not at all, but it attracted some national attention to a tempest engulfing a state famous for its balmy climate.

What outsiders don’t see is the way island homes are tightly arrayed in hilly, wooded terrain, targets for damage from wind and gushing, overflowing streams.

Is there work for the city to do, improving its surveillance and maintenance of storm drains and culverts? Absolutely.

But certainly it’s also time for home and business owners to take stock of their own risks and vulnerabilities, now that the sun is again drying out the soggy landscape.