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El Nino has brought a mixed bag of effects to US

This El Nino has been one of the strongest on record, but it has so far not been enough to completely alleviate the effects of drought and declining snowpack, and it seems to be making flooding worse across the coastal United States.

The morning commute on Lankershim Boulevard in Studio City, California, as drivers navigate large puddles of water from a passing storm on March 7, 2016.
Mark Boster | Los Angeles Times | Getty Images
The morning commute on Lankershim Boulevard in Studio City, California, as drivers navigate large puddles of water from a passing storm on March 7, 2016.

A group of scientists from the National Oceanographic and Oceanic Administration held a press call with reporters Wednesday to discuss the various impacts the pattern has had. Here are some highlights.

1. Flooding: El Nino is compounding the effects of sea-level rise and flooding coastal communities.

In general, flooding is becoming more of a problem for coastal communities around the United States, and some areas are dealing with recurring floods even when there are no storms or rain observed in the region, according to William Sweet, an oceanographer for NOAA's National Ocean Service. These floods are often called "nuisance flooding" or "sunny day flooding."

NOAA has around 200 tide gauges around the country, including those in the Great Lakes region. These gauges are reporting that the number of days per year where nuisance flooding is occurring somewhere in the country has increased rapidly over the last 50 years.

"El Nino means more East and West Coast tidal flooding," Sweet said. "On the West Coast we see high sea levels for months at a time, and this increases the reach of typical storms and tides. On the East Coast this is bringing more northerly winds, more storms and more storm surges."

He added that "El Nino is likely to become more frequent in the future, compounding the effects of sea-level rise."

2. Mountain snowpack levels are still pretty low: El Nino-related precipitation has brought some snow to mountain ranges in parts of the country compared with recent dry spells, but not yet enough to stop gradual declines.

"We do have snow across the Sierras, the Cascades and much of the Rockies, but we are actually at all-time lows or close to average in many locations," when compared with historical averages since 1920, said Sarah Kapnick, a physical scientist for NOAA Research.

Mountain snow is not only good for skiing. It is vital to supply water during dry periods and important for providing habitat for wildlife such as wolverines that need snow to survive.

Short and mild winters in many regions over the last two years have caused mountain snowpack to melt too early, preventing it from reaching its full potential.

3. California has more rain, but not all its water problems are solved. Major reservoirs in California are doing much better than they had been during the state's severe drought over the the last few years, said Martin Hoerling, a research meteorologist for NOAA Research. And snowpack in the Sierra Nevada mountain range is up from the extremely low levels observed during the drought.

But 2011-14 were the driest four consecutive years on record in California, and El Nino has not made up the difference everywhere.

Users that depend on groundwater are unlikely to see a recovery, Hoerling said. During the drought Californians became especially reliant on groundwater and supplies — which had been dwindling before the drought — became depleted.

And while strong El Ninos tend to be wetter, an El Nino pattern will not necessarily bring rain. Two of the state's driest years on record occurred during El Ninos, he said.