It snowed here yesterday, but the Yves Saint Laurent fashion show was heated.

It was the grand finale of the French ready-to-wear show in more ways than one, with tempers stretched to the breaking point by long working hours, the cross-city trek between shows, instense competition among buyers for the good new styles, and a general concern about high prices and the weakened dollar.

So when Pirre Berge, Saint Laurent's business manager, ordered cameras away from the side of the runway yesterday, the photograhpers, as usual, put up a fuss.

First Berge grabbed the equipment of a female photographer and handed it to an aide who marched it off the runway. A few minutes later - after announcing with great irritation that he would not start the show until the photographers were out of sight - he bent over to grab the collar of an Associated Press photographer who would not budge. Berge raised his fists and Remy Labbe de la mauviniere, the photographer, did the same. The other photographers, crouched by the runway, cheered their coleague. "You pig," shouted an English photographer.

A standoff of about 10 minutes ensued, but efin, the show began.

The curtain-raiser Sturm und Drang was soon forgotten with the success of the YSL show, which is what keeps the buyers and reporters coming back each season. Saint Laurent is clever at tapping the mood of the moment and turning it out in the most attractive package around - nothing too hard for his customers to understand, and enough news to lure their hundreds of dollars (a basic silk shirt alone at YSL's Rive Gauche boutiques now costs $195).

As Saint Laurent goes, so go a great many American manufactureres and, wittingly or otherwise, a tremendous number of women. So what is being offered for all?

Blouson jackets in wool, black leather and two-color satin worn with pants and skirts.

Updated classics, including sweater sets with the Carter cardigan, apadded-shoulder school uniform blazer, a kilt that now wraps and ties, a criss-cross belted skirt, a roomier, classic boycoat, and lots of plaids.

Opne ponchos in lightest-weight wool that wrap around everything.

Tooled leather right from a cowboy boot, now in blousons and jackets and best in natural leather, though it is seen in bright colors too; to be worn with day or evening clothes.

Saint Laurent has hiked his hemline up to just belwo the knee for a new proportion with his broader shoulder styles. Then for disco dancing he lets them climb right up to mid-tigh - you should pardon the expression, "mini" length.

Many of the evening clothes are see-through and others are in a light-weighted fabric that is satin on one side, crepe on the other, by Abraham, tha tseems to waft over the body. Other alternatives are smoking jackets or tuxedos.

There is plenty of black, plenty of olive drab - he's entitled, he did it first - and plenty of wonderful broad strokes of color in different pieces of fabric.

Still around, too, are printed, quilted jackets, shawls and wrap-belted boots.

And whether fashion or fetish, some new accessories come straight from your local S and M shop: studded bracelets and gauntlet cloves.