Triple whammy of snow, ice and sleet in store for millions across South and Midwest.

 Parts of Illinois were inundated with more than a foot of snow, while Indiana had tallied more than 11 inches.

Indiana: After getting slammed with more than 11 inches of snow, South Bend could see an additional 2 to 6 inches.

Buffalo, New York: This upstate region could see between 7 and 13 inches of snow, which is expected to peak Thursday afternoon through evening.

Cincinnati: This part of Ohio may see up to 0.3 inch of ice.

Little Rock, Arkansas: The city could get up to a half inch of ice in addition to an inch each of snow and sleet.

The area could also reach half an inch of ice.

Memphis, Tennessee: An additional quarter inch to half inch of ice are expected Thursday, when conditions are expected to peak between 4 a.m. and 1 p.m. About one tenth of an inch of ice has already been reported.

(CNN)A massive storm pummeling a large swath of the US has already dumped heavy snow and continues to threaten parts of the Midwest and South on Thursday with a triple whammy of snow, ice and sleet that could make travel miserable and leave many in the dark.

St. Louis: The city could see between 5 and 8 inches of additional snow Thursday after already getting about 4 inches in isolated areas.

Chicago: The Windy City could see up to 4 inches of additional snow pile on top of the nearly 9 inches that already fell.

In Indianapolis, where up to 3 more inches of snow could fall, peak conditions will also last through 6 p.m. About 4 inches have already fallen, with some areas seeing as many as 8 inches.

Plus, about 1 inch sleet and snow -- each -- is projected to fall.

In Austin, ice will pile up to about a quarter of an inch and sleet may reach a half inch.

Here is forecast information from CNN meteorologists Robert Shackelford and Mike Saenz for some cities in the storm's path:

    Texas: Dallas may see up to a half inch of ice.

Louisville, Kentucky: Up to half an inch of ice is expected to form.

Peak hours are expected between 3 a.m. and 11 a.m.

    Oklahoma City: A record daily maximum snowfall of 3 feet was already measured and another four inches of snow is possible.

Snow and sleet are projected to fall between 3 and 6 inches.

Freezing rain and sleet are projected to peak around 7 a.m. Thursday.

"A corridor of heavy ice (rain/freezing rain) accumulation is likely from Texas through the Ohio River Valley, especially from eastern Arkansas northeastward to western Kentucky," the NWS warned Wednesday.

Heavy snow began falling Tuesday and more than 20 inches had piled up in the Colorado Springs area, according to the National Weather Service (NWS).

"The system will be prolonged with several rounds of winter weather lasting through Friday for portions of the central U.S. before shifting to the interior Northeast," the NWS said Wednesday.

Leaders of the state's power grid -- Electric Reliability Council of Texas, or ERCOT -- reassured Texans Wednesday that they anticipate to be prepared to handle the high demand the storm will deliver but also warned there may be local outages unrelated to capacity.

The powerful storm is also curtailing air travel Thursday, which is projected to be one of the 10 worst days for air travel over the past year, with more than 40% of flights already canceled as of Wednesday afternoon at more than a dozen major US airports from Texas to Ohio, according to data from FlightAware.

And some areas, including Texas, are expected to feel those impacts through Saturday afternoon.

Areas seeing those conditions can also expect to experience below freezing temperatures in the days after the wintry mix ends.

Here's when and where to expect 'several rounds of winter weather'

As the storm system pushes farther east, forecasters say it will deliver a variety of winter weather hazards.

The system's reach is so expansive that more than 100 million people across at least 25 states were under winter weather alerts as of early Thursday from the Mexican border to New England.

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"With frozen precipitation there is always a chance for local outages caused by things like ice on wires or fallen tree limbs.

These local outages are not related to the amount of available electricity generated and put on the grid," interim CEO Brad Jones said in a news release.

"The combination of the volumes of snow, high winds, and frigid temperatures make travel near impossible in some areas of the state with several highways shutdown from vehicle crashes and jack-knifed semi-trucks," Kevin Sur, spokesperson for the Illinois Emergency Management Agency, told CNN.

Travel is already miserable

Dangerous travel conditions were already seen Wednesday in Illinois, where officials closed parts of several highways after crashes led to some injuries.

In Springfield, a train crashed into a car that became stuck on the tracks due to snow Wednesday night.

The driver -- the only person in the car-- was able to get out in time, Springfield police said, noting no injuries were reported.

CNN reached out to Amtrak for more information.

Amtrak canceled multiple train routes Wednesday and Thursday in and out of Chicago, including the Cardinal Train 51 to New York.

The route between St. Louis and Kansas City is also canceled, Amtrak said.

The heavy mixture of precipitation could deliver power outages, tree damage and dangerous travel conditions, the forecasters said.

In Texas, the storm will test the state's power grid, which suffered lengthy and widespread outages last February when a snow and ice storm left thousands without power for weeks and 246 people died, including many from hypothermia.

There were nearly 48,000 homes and businesses without power in Texas as of early Thursday morning, according to PowerOutage.us.

More than 16,000 outages were reported in Oklahoma and nearly 12,000 in Arkansas.

Conditions could potentially peak through Thursday afternoon.

Peak conditions will persist though 6 p.m. Thursday.

Peak conditions will last through 11 a.m. Thursday.

Snow will peak between 7 a.m. and 10 a.m.

The peak is projected to be Thursday morning when freezing rain will change to snow by afternoon.