Earth was blasted over the weekend by one of the most extreme magnetic storms of the current 11-year solar cycle and by the worst solar radiation storm since 1991.

The storms caused problems for satellites, triggered voltage fluctuations in some electric power systems, blacked out radio communications for commercial fishing boats and made the northern lights visible at mid latitudes, including Europe and as far south as St. Louis in the United States.

Both storms abated Sunday July 16 as the orientation of the interplanetary magnetic field between the sun and Earth changed to "protect us from further magnetic storming," said Craig Sechrest, a forecaster at the National Oceanic and Atmospheric Administration (NOAA) Space Environment Center in Boulder, Colorado.

During the storms, solar wind speeds at times reached 620 miles (1,000 kilometers) per second, which is equal to 2.24 million m.p.h. (3.6 million kilometers per hour) -- roughly twice the normal speed of the solar wind.

Many measurements during the storms were "the highest numbers we've ever seen," Sechrest said.

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Plots of presumed auroral activity made by a NOAA satellite showed the northern and southern lights pushed far from the poles and should have been visible to mid latitudes of 40 degrees or even closer to the equator.

NOAA snapshot of Sunday night's auroral activity.

The Space Environment Center makes space-weather forecasts and does not necessarily receive reports of the effects of such weather. But forecasters nevertheless heard the auroras were visible as far south as Champaign, Illinois and St. Louis, Missouri, Sechrest said.

An internet web page that receives such reports also listed aurora sightings in Russia, Germany, southern England and France.

Clouds and the full moon likely prevented aurora sightings in many areas.

Sechrest and forecaster Kent Doggett said U.S. GOES weather satellites suffered static due to the rain of proton radiation, which slightly degraded weather pictures.

"I am certain there have been many different satellite effects," including damage from radiation and electrical charging that might not show up for days or more, Doggett said.

But he said commercial satellite companies rarely report damage publicly. Soon after Friday's flare, however, another NOAA official said he had received reports of the solar radiation interfering with devices used to orient certain communications satellites.

Doggett and Sechrest also said NOAA had scattered reports from electric power companies in the U.S. northeast that the geomagnetic storm caused some voltage fluctuations that required power to be re-routed. But as far as they knew, there were no blackouts.

"To some extent, that is to our credit because we warned people they could take mitigating actions," Doggett said.

NOAA also received some reports of blackouts of radio communications and degraded navigation signals by commercial fishing vessels, but Doggett said he did not know where such incidents occurred.

After Friday's massive solar flare, NOAA officials said the resulting solar radiation storm was the strongest since 1994. It was rated severe, or S4, on a scale that goes from minor S1 to extreme S5. But Sechrest and Doggett said Sunday that later measurements showed it was stronger than the 1994 proton storm and was indeed the strongest since 1991.

At the proton storm's peak at 8:30 a.m. EDT (12:30 GMT) Saturday, satellite instruments measured 24,000 particle flux units, compared with 43,000 measured during the 1991 storm, Sechrest said.

The sun currently is near the maximum of its 11-year cycle of sunspots and activity. Scientists do not really know exactly when "solar maximum" occurs until analyzing the entire active period months later, Sechrest said.

Doggett said he had not reviewed previous geomagnetic storms during the current solar cycle, so he could not say if the extreme storm over the weekend was the worst so far this cycle, but it certainly is "one of the most extreme."

Despite the intense solar activity, the public is largely unaware of the turmoil it causes in space around the Earth, so the significance of even an extreme geomagnetic storm "for Joe Public is probably none," Doggett said.

Several more small-to-moderate flares shot off the sun Saturday. Space-weather forecasters predict an 80 percent-chance of moderate solar flares and a 35 percent-chance of major solar flares through July 18.