(Bloomberg Gadfly)—With the help of its Prime membership program, Amazon.com Inc. has trained shoppers to open its app at the very moment they realize they need toilet paper or Tide.

Now that same frantic, need-now-buy-now shopping behavior is affecting customers of bricks-and-mortar stores, as well.

Urban Outfitters Inc. CEO Richard Hayne told analysts he had never seen shopping patterns as choppy as they were during the quarter that ended in January, contributing to flat comparable sales and lower-than-expected earnings results. Shares of Urban Outfitters, No. 39 in the Internet Retailer 2016 Top 500 Guide, fell 10% Wednesday after Urban Outfitters’ call with analysts on Tuesday. Amazon is No. 1 in the Top 500.

Sales at Urban Outfitters were up in November, with double-digit comparable sales gains on Black Friday and Cyber Monday, leading Hayne to think “things were looking very good.” Then came December, and demand plummeted. Shoppers came back to buy last-minute Christmas gifts, but ghosted again shortly after the New Year began.

Urban Outfitters isn’t alone. In the past year, shopper traffic has mainly spiked in weeks right before holidays, when customers rushed to stores for last-minute gifts, according to data from Prodco.

Discounts also tend to be higher around such times, which helps drive traffic:

But it’s clear that the mom who buys Christmas presents throughout the year or winter coats for her kids in July is long gone. Internet-inspired behavioral changes have pretty much erased the concept of shopping seasons, such as “back to school” season or the holiday shopping period. As more shoppers go online, these changes will likely accelerate.

Urban Outfitters said it expects the percentage of sales online to match those in stores in the next three years, a sign the retailer is smartly adjusting to its customers’ habits. It also acknowledged online sales aren’t all additive: “Digital shopping is partially replacing store shopping,” driving discounts, depressing sales and eroding margins, Hayne said.

Likening the state of the retail industry to the 2008 housing bubble, Hayne said retailers have built too many stores for too long, and “that bubble has now burst.” It’s an apt analogy. It suggests even more bankruptcies and store closings will come as the winnowing of the retail industry continues.

But it’s important to realize retailers operating physical stores aren’t just suffering because online shopping has changed where customers shop. As Urban Outfitters’ example shows, it’s also because digital shopping has fundamentally altered how people shop.

This column does not necessarily reflect the opinion of Bloomberg LP and its owners.