Yesterday was the day when firefighters all over Japan dress up like firefighters from Edo times and dangle hazardously from ladders in order to remind people that fire is dangerous.

This is called the dezome-shiki (出初め式); "Ceremony of First Appearance", perhaps.

The ladder was an indispensable fire-fighting tool in the Edo Period. This was because the main method back then was to tear down the surrounding buildings to prevent fire from spreading, so there was a need to climb up onto roofs.

(This is also why the builders and the firefighters tended to be the same group of burly hard-drinking men, obviously.)

Shibata Ryūsei's Edo remains (残されたる江戸) on fire and dezome (in sloppy translation):

On the Musashino Terrace, the dry wind (karakkaze) that comes down from Mt Tsukuba blows and blows from the end of autumn right through the third month of winter, not stopping even when the flowers bloom; it isn't rare for it to ruin picnics all through spring.

[...] It was bad enough when the karakkaze made mischief by toying with a passing young lady's skirt or teasing her hair out from her okoso-zukin, but all too often you would hear the jaang! as its red tongues came out to lick the whole area, as if to devour Edo whole. Even the tough guys who called it the "flower of Edo" didn't have time to kid around when disaster struck their own homes -- no, you had to fight it then as if your life depended on it. And so when the karakkaze blew at night people would watch their hearths carefully; in Mukōjima they got protective charms [of Hi-no-Kagu-Tsuchi no Kami] from Akiba Shrine and put them in the kitchen altar next to Kōjin-sama; for as long as Edo had been a going concern, people had been growing more and more determined not to get caught out again, which meant covering all the angles.

"How do you like that, blowing like a bitch again. Let's just hope it doesn't go jang! tonight," they'd say, and on those nights everyone was on edge, jumping at the sound of cooking pots. [...]

The firebell's never a pleasant thing to hear, whatever the occasion; even when they ring it during the firefighters' dezome-shiki at New Year's, and you know that's all it is, it still makes you kind of edgy.