The blizzard that swept through the Northeast on Sunday and Monday delayed $1 billion in retail spending, according to research firm ShopperTrak, but won’t derail a holiday shopping season expected to be the best since 2007.

The effect won’t be as bad as last year’s pre-Christmas snowstorm that similarly paralyzed parts of the East Coast. That cost retailers an estimated $2 billion, according to weather research firm Planalytics.

About $10 billion in retail sales usually occurs Dec. 26-27, ShopperTrak says. Bad weather likely delayed about 10 percent of that.

The storm’s effects weren’t enough to change ShopperTrak’s estimate for a 4 percent gain over last year in revenue for the Nov. 1-Dec. 31 holiday season. Retailers will still see much of the spending when shoppers return to stores as streets are cleared and transportation restored.