Before, after photos show California landscapes making a comeback from drought Once dried-out fields have returned to their lush state after the rainy season.

 -- Before-and-after photos of various landscapes in California show what a difference the deluge of winter rain has made after years of drought.

Photos taken by Getty Images photographer Justin Sullivan in the summer of 2014 -- in the middle of the drought -- show brown fields and dried-up reservoirs. They differ starkly from the photos taken by Sullivan Tuesday.

The summer of 2014 was the most "severe" period during California's four-year drought, said Amir AghaKouchak, associate professor, civil and environmental engineering, at the University of California, Irvine.

While California's groundwater resources will still take a while to "recharge and recover," AghaKouchak added that "overall ... the drought is over."

Gov. Jerry Brown ended the drought emergency for most of the state last week.

Sullivan, who is based in San Francisco, told ABC News that there was a vast difference from 2014 to now.

"It was so brown everywhere," Sullivan said when describing what it was like to snap the photos in 2014. For years, it seemed like the landscape would "get green for a couple of months," but would then return to its brown state, he said.

AghaKouchak, who spends a lot of time outdoors, said this is "probably the greenest" that he has seen landscapes in Southern California in the past four or five years. There is even a field on the UC Irvine campus that is sprouting yellow flowers, he said.

It was "amazing" to see everything so green, Sullivan said.

AghaKouchak said the photos were "not surprising at all" considering the Golden State's recent weather.

"It's because of all the rain," AghaKouchak said, adding that California sees most of its rain between December and March. Since November, when California's rainy season began, the landscape has "changed slowly over time."

Sullivan said that one of the biggest differences he saw was in Lake Oroville, which was "basically empty" when he first took the photos in 2014. AghaKouchak added California's reservoirs are now in "much better shape" after the rainy winter.

In February, areas near the Oroville Dam were evacuated after the dam was damaged by excess water.

ABC News' Phaedra Singelis, Jeff Swartz and Liz Kreutz contributed to this report.