A vast storm system Wednesday night may bring snow from eastern South Dakota into northeast Nebraska, northwest Iowa, and central and southern Minnesota, to include the Twin Cities, The Weather Channel reported. Four to eight inches of snow could fall Wednesday night alone in the Sioux Falls to Minneapolis corridor.

Light snow could reach as far east as northern Wisconsin, The Weather Channel reported.

Farther east, in upstate New York, Buffalo could see a brief period of freezing rain Thursday morning.

Earlier Wednesday, the storm pounded the Dakotas with snow, coated Oklahoma with rare spring ice and took aim at parts of the Mid-Atlantic and South.

Snow, freezing rain and strong winds snapped trees, broke power poles and left cars sheathed in ice in South Dakota, and the city of Sioux Falls declared a state of emergency.

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Farther south — and much more unusually — ice coated roads in Oklahoma, all the way down to the Red River border with Texas.

“For April, that is really amazing,” said Tom Niziol, a meteorologist and winter weather expert for The Weather Channel.

It all made for a messy day of travel in the Great Plains and the Midwest. Chicago O’Hare, a hub airport for the central United States, reported almost 500 flight cancellations.

Dirk Lammers / AP

Icy branches partially block a city street and fall amid parked cars in Sioux Falls, S.D.

As the storm system lumbers eastward, powerful thunderstorms are expected later Wednesday and overnight in Pennsylvania and Maryland, including Philadelphia and its suburbs.

It has been unusually cold this week in the West and unseasonably warm in the East, including temperatures pushing 90 degrees Wednesday in Washington. That warm air makes the weather system more dangerous.

“There will be more than enough fuel for these storms,” said Carl Parker, another meteorologist for The Weather Channel.

A line of late-day storms was expected to sweep across Arkansas on Wednesday afternoon, threatening to dump damaging hail and perhaps spawn tornadoes before pushing out of the state in the evening.

The same storm system has already produced bizarre weather elsewhere in the country.

Earlier this week, the temperature fell 55 degrees in Denver in less than 24 hours. Gusty wind nudged 21 cars of a freight train off the tracks in Nebraska. And snowflakes the size of cotton balls fall in Marshall, Minn., NBC affiliate KARE in Minneapolis reported.

This story was originally published on Wed Apr 10, 2013 6:32 AM EDT

A winter storm that socked the Midwest last week moved across the Northeast on Monday, bringing light snow, ice and rain to the region, forecasters said. 

The wintry mix hit from eastern Pennsylvania through southern New England, The Weather Channel reported. Major accumulations of snow were not anticipated.

Snowfall of up to 3 inches is possible from central and northern New York through central and northern New England.

The weather will change to sleet and freezing rain in southern New York, northeastern Pennsylvania and northern New Jersey, and roads could be slick.

Morning sleet and freezing rain forecast to become afternoon rain in western Virginia, central and southeastern Pennsylvania, southern New Jersey, Maryland and Delaware.

Stan Honda / AFP - Getty Images

Snow falls lightly in Manhattan, N.Y., on Monday, January 28, 2013. Temperatures near freezing are making it tricky for commuters and pedestrians.

The mixture of freezing rain and sleet in the Northeast follows a weekend of disruption in the Midwest, with many flights in and out of Chicago, Minneapolis and St. Louis being grounded by icy runways on Sunday, according to Reuters.

Hundreds of churches across Iowa cancelled Sunday services as sidewalks were turned to sheets of ice by the storm that covered the region, Reuters said.

Meanwhile, a storm bringing rain to the southwest Monday was expected to move into the southern Plains and southern half of the Mississippi Valley on Tuesday.

Damaging wind gusts, hail and tornadoes are possible from eastern Oklahoma and northeast Texas to central and southern Illinois, western Kentucky, western Tennessee, northwest Mississippi and northern Louisiana Tuesday.

In the northern Plains, as many as 4 to 6 inches of precipitation was expected from eastern North Dakota to northern Minnesota Monday afternoon through Tuesday.

Elsewhere, heavy mountain snows and strong winds were forecast in mountain areas across the West that will result in significant drifting snow, which has prompted an avalanche watch for a portion of the Colorado Rockies.   

Updated at 3:30 p.m. ET: Winter storm warnings were issued Saturday for parts of Maryland and Pennsylvania in the East and Colorado and New Mexico in the West.

The National Weather Service warned of snow-covered roads with 1 to 3 inches of snow expected to fall in affected areas in the East and locally higher amounts.

In some mountainous areas of Colorado, the NWS said it expected heavy, blowing snow with total accumulations of 10 to 20 inches.

Read more at weather.com

Some 8 to 12 inches of snow were expected to hit the northern mountains of New Mexico, the weather service said.

The Weather Channel said the last week's cold air invasion set the stage for this latest winter storm: "As an upper disturbance ejects out of the southwestern states, it will run into southerly winds on the backside of a high-pressure system centered over the Eastern Seaboard." 

Winter storm watches were also issued for parts of Illinois, including Chicago, Wisconsin, Minnesota, and Iowa.

The weather service forecasts freezing rain will develop in that area, from central Iowa to southern Wisconsin, northern Illinois and southern Michigan on Saturday night or Sunday. Travel conditions could be hazardous this weekend, NWS warned.

“Further north into Minnesota and Wisconsin, a couple inches of snow are possible before changing over to freezing rain and then rain,” said meteorologist Michael Palmer of The Weather Channel. Palmer said rain, sleet and snow could also hit the Plains and Midwest over the weekend.

Palmer warned there was the potential for a up to 0.5 inch of ice accumulation for Omaha, Des Moines, St. Louis and Chicago before rain moved in.

“The icy mixture will affect Detroit, Pittsburgh and Buffalo going into Monday,” he said.

“The band of moisture will continue to shift northeastward through the Great Lakes Sunday night and Monday with a variety of wintry weather,” he added. “Rain breaks out in Oklahoma and Kansas late Saturday and spreads northward into the colder surface air Sunday for an icy mixture” for parts of Nebraska, Missouri, Iowa, and Illinois.

Palmer warned of “significant travel issues with very slick roadways” and also said some affected areas could see power outages Saturday night through Sunday.

However, he said “a surge of warmer air" would arrive in the Plains and Midwest by late Monday with most areas seeing the ice and snow melt.

NBC staff writer Isolde Raftery contributed to this report.

Matt Rourke / AP

A runner crosses a street during a winter snow storm, Friday, in Philadelphia.

Capping off a brutal week of frigid conditions and subzero wind chills, residents across much of the country on Friday were still experiencing some of the coldest temperatures in years — with southern states getting a rare icy blast.

Peak temperatures from the Northeast to the Midwest were slated to range from single digits to the 30s, and forecasters said freezing air temperatures and the chance of precipitation could mean snow in both regions.

"This is actually quite an impressive mass of cold air," Richard Castro, a meteorologist at the National Weather Service told NBCChicago.com.

By mid-afternoon on Friday, Pennsylvania was feeling the first of a "widespread storm, impacting the entire state," said state's transportation department spokesman Steve Chizmar.

Snow was falling over most of the state, and forecasters predicted a total of 1 to 4 inches through Saturday morning, while transportation department crews stayed busy plowing and salting the roads.

Hundreds of schools in the state dismissed classes early Friday.

Only a light dusting, if any accumulation, was expected in New York City, where real-feel temperatures were below zero Friday morning, NBCNewYork.com reported.

Slideshow: Deep Freeze

Timothy A. Clary / AFP - Getty Images

A man photographs the fountain at Bryant Park in New York on Friday as the arctic air has turned the fountain into an ice sculpture.

Launch slideshow

In the Midwest, one of the first snowfalls of the season in Chicago created a few slick spots on the roads Friday morning, causing at least a dozen accidents, including an eight-vehicle crash, NBCChicago.com reported. Only minor injuries had been reported.

Though little snow accumulated it was still record breaking. The 1.1 inches recorded Friday morning broke the city’s 335-day stretch of no more than an inch of snow accumulation in one day.

The National Weather Service had winter weather advisories in effect for the eastern seaboard from North Carolina to southern New Jersey, and issued blizzard warnings for northern Georgia.

Parts of Kentucky were reporting as much as half inch of ice accumulation, Weather.com reported. Slick roads in the southeast of the state were making driving hazardous, causing more than 100 accidents in Pulaski County alone, it said.

Tennessee was also slick with ice in the east, and reported some power outages, while freezing rain caused a number of school systems in central and southern Kentucky to cancel classes, according to WLEX-TV.

Because cold temperatures can be dangerous, officials advised residents to heed cold-weather tips, including wearing gloves, wearing a mouth covering to protect the lungs from bitter cold air, layering loose-fitting, warm clothing and wearing a hat to retain body heat.

Animal advocates also urged pet owners to only take elderly dogs, puppies and short-haired dogs outside when it is absolutely necessary. If a dog whines frequently or keeps lifting its paws up while on a walk, it may need boots. Cat owners should keep their animals inside at all times in such bitter cold, NBCChicago.com reported.

The forecast for next week called for some relief from the arctic temperatures of late, beginning with sunny skies and temperatures hitting the mid-40s to 50s by the middle of the week. 

Kari Huus, NBC Staff Writer, contributed to this report.

A dam release in western North Carolina triggered a rare sight Tuesday as the spewing water produced rainbows and an icy show in the middle of winter.

After days of heavy rain saturated the area last week, river managers sought to create more storage room in Fontana Lake to prevent further flooding in the face of more rain in the long-range forecast, NBC station WBIR in Knoxville reported.  

"This event was so big, we got very high in the reservoir and we've got to move that water out," Tennessee Valley Authority General Manger of River Scheduling Chuck Bach told the Knoxville News Sentinel. "Sometimes we can't get enough water out fast enough through turbines, so we run the turbines first to generate hydroelectricity, and we augment it with either sluicing or spilling."

So for the first time in 13 years, the TVA began using a sluice tube behind the dam to lower water levels about one foot per day in the reservoir.  

That works out to about 128,000 gallons of water released per second, Bach said.

And to keep the force of the water from scouring out the bed of the Little Tennessee River, a ramp at the bottom of the sluice tube diverted the water, TVA spokesman Travis Brickey said.

In doing so, a sort of rooster tail of gushing water was created that gave off an enormous amount of spray that turned to snow and freezing droplets in the bitter air, which encased nearby trees and grass in a layer of ice.  

“It was its own winter weather maker,” Brickey said. “It was like a big, giant ice machine. It being so cold overnight and today, it froze to a lot of stuff.”

In the sunlight, the blowing mist also created a vivid rainbow effect.

“It made it more spectacular because of the way that it looked,” Brickey said. “Word got out, because we do it so rarely, people were out taking pictures of it.” 

After being emptied, the water moves through the river system past Knoxville and into the Ohio River. 

Five solid tips from people who told authorities that distinctive tattoos helped them recognize a woman seen in photos released Thursday as part of a child molestation investigation led to an arrest in an 11-year-old case involving "widely circulated" child pornography images.

Letha Mae Montemayor, 52, was taken into custody Thursday night outside an apartment complex in North Hills in the San Fernando Valley.

Authorities said they believe the woman is the individual -- identified as "Jane Doe" in a criminal complaint filed Monday -- who appears with an unidentified male in a series of photographs released Thursday afternoon as investigators hunted for leads in the child pornography case.

"Just after ICE’s nationwide plea for public assistance, five separate community tips led to the arrest of Jane Doe," said U.S. Immigration and Customs Enforcement (ICE) Director John Morton. "This arrest would not have happened without the public’s help, and it demonstrates how much individual citizens can do to help law enforcement attack crime."

Also on NBCLosAngeles.com: Second suspect arrested in child porn case, ICE says

An appearance in federal court for Montemayor, charged with one count of making child pornography, was scheduled for Monday.

A neighbor of Montemayor's who did not want to be identified said the suspect was a "hoarder" who "did not take care of her body well" and was "rude to all the children."

About 10 hours before her arrest, Morton and other law enforcement agents conducted a news conference regarding "Operation Sunflower," a recently concluded child sex crimes investigation that led to more than 240 arrests. During the news conference, authorities released images of a man and tattooed woman wanted in connection with a child molestation case authorities said occurred about 11 years ago, possibly in Los Angeles.

"The (tipsters) said they recognized the face, the tattoos," said Homeland Security Investigations Special Agent in Charge Claude Arnold.

"They were very confident that it was she. We expect that it would be more difficult because they were older images, but we were optimistic because they were good images."

ice.gov

These images released by federal authorities as part of a child porn investigation led to the arrest of a woman in Los Angeles.

The woman's tattoos -- a sleeping cat, butterfly and other designs -- are visible in the photographs released Thursday.

123 child victims of Internet sex abuse identified, US officials say

But other clues in the background of the images, discovered by Chicago Homeland Security agents in 2007 and passed along to LA agents, prompted investigators to focus on locations in the San Fernando Valley. Forensics analysis of the images, conducted by the National Center for Missing and Exploited Children, revealed details in the pictures, such as close-ups of the tattoos, a calendar from a store and a phonebook.

The criminal complaint alleges that "Jane Doe," now identified as Montemayor, was involved in the production of child pornography images that were "widely circulated" online. The images depict the sexual molestation of a girl, who appears to be about age 13, according to ICE.

Authorities have not identified the victim or male subject.

"We still want the public’s help in identifying John Doe and the victim in the disturbing series of images that continue to be circulated on the Internet," said U.S. Attorney André Birotte.

Call 866-347-2423 or visit this tips form to provide information. Click here to view the ICE wanted poster.

Alex Wong / Getty Images of North America

U.S. Immigration and Customs Enforcement Director John Morton speaks as John Ryan, CEO of the National Center for Missing & Exploited Children, left, listens during a news conference in Washington on Thursday.

In just over a month, more than 120 sexually exploited children -- one just 19 days old -- were identified in an international operation that found them depicted in child pornography on the Internet, U.S. officials said Thursday.

In Operation Sunflower, led by agents from Immigration and Customs Enforcement’s Homeland Security Investigation unit from Nov. 1 to Dec. 7, 123 victims of child sexual exploitation were identified, ICE Director John Morton said at a press conference in Washington. 

Of that group, 44 children had been living with their abusers, and 79 children were exploited by people outside of their home or were victimized as children and are now adults. Seventy female and 53 male victims rescued; 110 of the victims were identified in 19 U.S. states and the rest were identified in six foreign countries.

“Results [of the operation] were significant but grim, a sad reminder to us all that child online exploitation is a real part of our lives and absolutely demands our full attention,” Morton said. “The rescues highlight the depth and global nature of this problem.”

In the investigation, HSI and partner law enforcement agencies arrested 245 people. Among them were a first-grade teacher from Chula Vista, Calif., and an airline pilot, NBCSanDiego.com reported.

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“As satisfying as the arrests have been, today is a day of mixed emotions because this operation is ultimately a tale of the perverse, pervasive and violent exploitation of children, very young children to satisfy a very dark pleasure of twisted adults,” Morton said. 

Of the victims identified during Operation Sunflower, five were under the age of 3, and one of those was just 19 days old. Thirty others were below the age of 10, officials said.

“The age of the victim has always been a problem. The Internet has just allowed a much greater immediacy to the abuse, and we’re seeing numerous instances of life child abuse that has been streamed over the Internet,” Morton said.

From the results of Operation Sunflower, named after ICE’s first successful case under the new Victim Identification Program, Morton said a few trends emerged.

Most notably, younger children were more often abused and more women were directly involved in carrying out the abuse, he said.

Watch the most-viewed videos on NBCNews.com

Additionally, the victims of child sexual exploitation increasingly have an international nexus, said John Ryan, CEO of the National Center for Missing and Exploited Children.

“The problem of child exploitation is hardly confined to the United States,” Ryan said Thursday. “The Internet has made this problem such that almost every case we touch and investigate has a very strong overseas component.”

"We know that there's more work to be done," Ryan said. "Anyone could know these victims, not knowing that they're being harmed. They could be your neighbors' children, your child's classmate, or even your own child."

Morton said the only answer to child exploitation is "a relentless fight."

"Whenever our investigations reveal the production and distribution of new child pornography online, we will do everything we can to rescue the victim and prosecute the abuser, even if takes us years or around the world to do it," he said.

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LA GRANDE, Ore. -- Nine people were killed and at least 20 others hospitalized on Sunday after a tour bus veered out of control on an icy stretch of freeway in eastern Oregon and rolled nearly 200 feet down an embankment, state police said.

State police reported that the driver apparently lost control of the charter bus around 10:30 a.m. on the snow- and ice-covered lanes of Interstate 84 and crashed through a guardrail before plunging down an embankment. The Oregonian newspaper reported that the bus  tumbled nearly 200 feet before coming to a halt.

Oregon State Police Lt. Gregg Hastings told the newspaper that about 40 passengers were on the bus at the time of the crash, which occurred near milepost 227 on Interstate 84 near Deadman Pass, according to the East Oregonian newspaper. 

Hastings told the East Oregonian that he learned the bus was returning to Las Vegas from British Columbia, Canada.   

Rescue workers used ropes to help retrieve the injured from the scene. Westbound lanes of I-84 were closed.

The Oregonian said 18 passengers were transported to St. Anthony's Hospital in Pendleton, about 13 miles northwest of the crash scene. Hospital spokesman Larry Blanc would not say if or how many passengers sustained life-threatening injuries, it said.

Three fixed-wing aircraft also were on standby at the Pendleton airport if needed to transport injured to hospitals elsewhere, state police said.

Authorities did not immediately identify the operator of the charter bus.

Oregon State Police / Reuters

Rescue personnel respond to the scene of a charter bus crash on I-84, east of Pendleton, Ore. in this photo released on Dec. 30. Police said the bus may have gone out of control on the highway before crashing through a guardrail and down an embankment.

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