California poppy fields at Lake Elsinore closed by officials as thousands of tourists turn up to take pictures

A small city in southern California was forced to ban tourists from visiting a golden poppy “super bloom” amid safety concerns as thousands tried to glimpse the amazing natural spectacle.

About 150,000 people flocked to the hills around Lake Elsinore, roughly a 90-minute drive from San Diego and Los Angeles, over the weekend.

Authorities were forced to shut down viewing of the colourful poppies on Sunday after massive traffic jams developed.

"It was insane, absolutely insane," said Mayor Steve Manos, who described it as a "poppy apocalypse."

Lake Elsinore had tried to prepare for the crush of people drawn by the super bloom by offering a free shuttle service to the top viewing spots, but it wasn't enough.

Roads leading to Walker Canyon became completely jammed with neighbouring areas even requesting police assistance to deal with the crush.

The city cancelled the shuttle service and then completely shut down access to the poppy-blanketed canyon, saying the weekend had become unbearable.

People left trails and started trampling flowers as the problems surfaced, and later #poppyshutdown began spreading on Twitter.

By Monday the #poppyshutdown announced by the city on Twitter was over and the road to the canyon was re-opened.

The super bloom is a rare occurrence that usually happens about once a decade because it requires a wet winter and warm temperatures that stay above freezing.