A snow plow removes a coating of slush on the plaza in front of the White House in Washington, U.S. March 21, 2018. REUTERS/Jonathan Ernst

A snow plow removes a coating of slush on the plaza in front of the White House in Washington, U.S. March 21, 2018. REUTERS/Jonathan Ernst

A worker clears snow and slush in Times Square in Manhattan in New York City, New York, U.S., March 7, 2018. REUTERS/Amr Alfiky

Workers clear snow and slush in the financial district during a winter nor'easter in New York City, U.S., March 7, 2018. REUTERS/Brendan McDermid

Workers clear snow and slush in the financial district during a winter nor'easter in New York City, U.S., March 7, 2018. REUTERS/Brendan McDermid

Workers clear snow and slush in the financial district during a winter nor'easter in New York City, U.S., March 7, 2018. REUTERS/Brendan McDermid

Workers clear snow and slush in the financial district during a winter nor'easter in New York City, U.S., March 7, 2018. REUTERS/Brendan McDermid

Workers clear snow and slush in the financial district during a winter nor'easter in New York City, U.S., March 7, 2018. REUTERS/Brendan McDermid

Samsung Electronics Chief Strategy Officer Young Sohn poses for a picture at Slush startup event in Helsinki, Finland December 1, 2017.REUTERS/Tuomas Forsell

Executive Director of Tencent Martin Lau (L) and moderator Clemency Burton-Hill listen to Supercell CEO Ilkka Paananen during a panel at Slush startup event in Helsinki, Finland, December 1, 2017.REUTERS/Tuomas Forsell

Executive Director of Tencent Martin Lau (L) listens to Supercell CEO Ilkka Paananen during a panel at Slush startup event in Helsinki, Finland, December 1, 2017.REUTERS/Tuomas Forsell

(L to R) SoftBankÕs Managing Director David Thevenon, Atomico CEO Niklas Zennstrom, firstminute capital co-founder Brent Hoberman and moderator Sophia Bendz attend a Slush startup event in Helsinki, Finland, November 30, 2017. REUTERS/Tuomas Forsell

SoftBankÕs Managing Director David Thevenon (L) and firstminute capital co-founder Brent Hoberman (R) listen to Atomico CEO Niklas Zennstrom during the Slush startup event in Helsinki, Finland, November 30, 2017. REUTERS/Tuomas Forsell

A man uses a mobile phone while eating an iced slush in Sliema, Malta, July 7, 2017. REUTERS/Darrin Zammit Lupi

Isle of Wight Festival - Isle of Wight, Britain - 11/06/2017 - A young reveller with a slush is seen during the Isle of Wight Festival in Seaclose Park. REUTERS/Tom Jacobs

Tech.eu founding editor Robin Wauters (L to R), Supercell CEO Ilkka Paananen, Spotify CEO Daniel Ek and Atomico CEO Niklas Zennstrom speaking in a panel at start-up conference Slush in Helsinki, Finland, November 30, 2016. REUTERS/Jussi Rosendahl

Tech.eu founding editor Robin Wauters (L to R), Supercell CEO Ilkka Paananen, Spotify CEO Daniel Ek and Atomico CEO Niklas Zennstrom speaking in a panel at start-up conference Slush in Helsinki, Finland, November 30, 2016. REUTERS/Mia Shanley

Tech.eu founding editor Robin Wauters (L to R), Supercell CEO Ilkka Paananen, Spotify CEO Daniel Ek and Atomico CEO Niklas Zennstrom speak in a panel at start-up conference Slush in Helsinki, Finland, November 30, 2016. REUTERS/Mia Shanley

Founder and CEO of King Riccardo Zacconi (R) speaks on stage at tech start-up conference Slush in Helsinki, Finland November 30, 2016. REUTERs/Mia Shanley

People gather near the entrance to the venue of Slush, one of Europe's biggest tech start-up conferences in Helsinki, Finland November 30, 2016. REUTERS/Mia Shanley

A unicorn, representing tech start-ups valued at over 1 billion dollars, is pictured at Slush, one of Europe's biggest tech start-up conferences in Helsinki, Finland November 30, 2016. REUTERS/Mia Shanley

Staff is working at Slush, one of Europe's biggest tech start-up conferences in Helsinki, Finland November 30, 2016. REUTERS/Mia Shanley

A woman walks on a slush and snow covered street in the SoHo section of Manhattan in New York January 26, 2016. REUTERS/Brendan McDermid

A street vendor walks through slush and snow on Broadway in lower Manhattan in New York January 25, 2016. REUTERS/Brendan McDermid

People cross a slush and snow covered street in lower Manhattan in New York January 25, 2016. REUTERS/Brendan McDermid

A street vendor walks through slush and snow on Broadway in lower Manhattan in New York January 25, 2016. REUTERS/Brendan McDermid

People cross slush and snow covered street in lower Manhattan in New York January 25, 2016. REUTERS/Brendan McDermid

People cross slush and snow covered street in lower Manhattan in New York January 25, 2016. REUTERS/Brendan McDermid

A woman in high heeled boots walks through slush in the Manhattan borough of New York City, January 25, 2016. REUTERS/Mike Segar

People navigate through the snow and slush during the morning commute in the Brooklyn borough of New York, January 25, 2016. REUTERS/Brendan McDermid

A man walks though a puddle of slush in Times Square in the Manhattan borough of New York, January 25, 2016. REUTERS/Carlo Allegri

Wolfgang Niersbach, president of the German Football Association (DFB) is silouetted against a huge illuminated World Cup Brazil 2014 soccer ball during the opening of the new German soccer museum in Dortmund October 19, 2015. Frankfurt's state prosecutor will look into bribery allegations concerning the 2006 soccer World Cup after a magazine report suggested a slush fund had been used to buy votes for the German bid in 2000, an official said on Monday. Der Spiegel magazine reported on Friday that Germany's bid committee, that included Franz Beckenbauer, head of the 2006 organizing committee, and Niersbach who was a vice president of the committee, had tapped into a slush fund of 6.7 million euros to buy votes at world soccer's governing body FIFA.Niersbach, Beckenbauer and the DFB have vehemently rejected the allegations as 'groundless' and have said the magazine had provided no evidence to back up its claims. REUTERS/Wolfgang Rattay

Wolfgang Niersbach, president of the German Football Association (DFB) attends the opening of the new German soccer museum in Dortmund October 19, 2015. Frankfurt's state prosecutor will look into bribery allegations concerning the 2006 soccer World Cup after a magazine report suggested a slush fund had been used to buy votes for the German bid in 2000, an official said on Monday. Der Spiegel magazine reported on Friday that Germany's bid committee, that included Franz Beckenbauer, head of the 2006 organizing committee, and Niersbach who was a vice president of the committee, had tapped into a slush fund of 6.7 million euros to buy votes at world soccer's governing body FIFA.Niersbach, Beckenbauer and the DFB have vehemently rejected the allegations as 'groundless' and have said the magazine had provided no evidence to back up its claims. REUTERS/Wolfgang Rattay

Wolfgang Niersbach, president of the German Football Association (DFB) attends the opening of the new German soccer museum in Dortmund October 19, 2015. Frankfurt's state prosecutor will look into bribery allegations concerning the 2006 soccer World Cup after a magazine report suggested a slush fund had been used to buy votes for the German bid in 2000, an official said on Monday. Der Spiegel magazine reported on Friday that Germany's bid committee, that included Franz Beckenbauer, head of the 2006 organizing committee, and Niersbach who was a vice president of the committee, had tapped into a slush fund of 6.7 million euros to buy votes at world soccer's governing body FIFA.Niersbach, Beckenbauer and the DFB have vehemently rejected the allegations as 'groundless' and have said the magazine had provided no evidence to back up its claims. REUTERS/Wolfgang Rattay

Wolfgang Niersbach, president of the German Football Association (DFB) stands next to the original ball of the 1954 soccer World Cup final, at the new German soccer museum in Dortmund October 19, 2015. Frankfurt's state prosecutor will look into bribery allegations concerning the 2006 soccer World Cup after a magazine report suggested a slush fund had been used to buy votes for the German bid in 2000, an official said on Monday. Der Spiegel magazine reported on Friday that Germany's bid committee, that included Franz Beckenbauer, head of the 2006 organizing committee, and Niersbach who was a vice president of the committee, had tapped into a slush fund of 6.7 million euros to buy votes at world soccer's governing body FIFA.Niersbach, Beckenbauer and the DFB have vehemently rejected the allegations as 'groundless' and have said the magazine had provided no evidence to back up its claims. REUTERS/Wolfgang Rattay

Wolfgang Niersbach, president of the German Football Association (DFB) stands next to the original ball of the 1954 soccer World Cup final, at the new German soccer museum in Dortmund October 19, 2015. Frankfurt's state prosecutor will look into bribery allegations concerning the 2006 soccer World Cup after a magazine report suggested a slush fund had been used to buy votes for the German bid in 2000, an official said on Monday. Der Spiegel magazine reported on Friday that Germany's bid committee, that included Franz Beckenbauer, head of the 2006 organizing committee, and Niersbach who was a vice president of the committee, had tapped into a slush fund of 6.7 million euros to buy votes at world soccer's governing body FIFA.Niersbach, Beckenbauer and the DFB have vehemently rejected the allegations as 'groundless' and have said the magazine had provided no evidence to back up its claims. REUTERS/Wolfgang Rattay

Wolfgang Niersbach, president of the German Football Association (DFB) stands next to the original ball of the 1954 soccer World Cup final, at the new German soccer museum in Dortmund October 19, 2015. Frankfurt's state prosecutor will look into bribery allegations concerning the 2006 soccer World Cup after a magazine report suggested a slush fund had been used to buy votes for the German bid in 2000, an official said on Monday. Der Spiegel magazine reported on Friday that Germany's bid committee, that included Franz Beckenbauer, head of the 2006 organizing committee, and Niersbach who was a vice president of the committee, had tapped into a slush fund of 6.7 million euros to buy votes at world soccer's governing body FIFA.Niersbach, Beckenbauer and the DFB have vehemently rejected the allegations as 'groundless' and have said the magazine had provided no evidence to back up its claims. REUTERS/Wolfgang Rattay TPX IMAGES OF THE DAY

A JetBlue aircraft is seen parked at JFK International Airport in New York February 22, 2015. Icy weather closed Kennedy Airport around 7:45 this morning as crews worked to clear the runways of ice, slush and snow according to local media reports from the Port Authority. The airport has since re-opened with lengthy delays for travelers. REUTERS/Shannon Stapleton (UNITED STATES - Tags: ENVIRONMENT SOCIETY TRANSPORT)

A Delta flight status video board is seen at JFK International Airport in New York February 22, 2015. Icy weather closed Kennedy Airport around 7:45 this morning as crews worked to clear the runways of ice, slush and snow according to local media reports from the Port Authority. The airport has since re-opened with lengthy delays for travelers. REUTERS/Shannon Stapleton (UNITED STATES - Tags: ENVIRONMENT SOCIETY TRANSPORT)

Travelers sleep in Terminal 4 of JFK International Airport in New York February 22, 2015. Icy weather closed Kennedy Airport around 7:45 this morning as crews worked to clear the runways of ice, slush and snow according to local media reports from the Port Authority. The airport has since re-opened with lengthy delays for travelers. REUTERS/Shannon Stapleton (UNITED STATES - Tags: ENVIRONMENT SOCIETY TRANSPORT)

Travelers sleep in Terminal 4 of JFK International Airport in New York February 22, 2015. Icy weather closed Kennedy Airport around 7:45 this morning as crews worked to clear the runways of ice, slush and snow according to local media reports from the Port Authority. The airport has since re-opened with lengthy delays for travelers. REUTERS/Shannon Stapleton (UNITED STATES - Tags: ENVIRONMENT SOCIETY TRANSPORT)

A morning commuter jumps over snow and slush during a winter storm during morning commute in the Brooklyn borough of New York February 2, 2015. The northeastern United States braced for the second major snow storm in a week on Monday after a huge winter system dumped more than a foot (30 cm) of snow in the Chicago area, closing schools from the Midwest to New England. REUTERS/Brendan McDermid (UNITED STATES - Tags: SOCIETY ENVIRONMENT)

A woman with bright yellow boots walks though puddle of slush in Times Square during a winter storm in the early morning hours in the Manhattan borough of New York February 2, 2015. REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY ENVIRONMENT)

A worker runs though a puddle of slush to a taxi he hailed in Times Square during a winter storm in the early morning hours in the Manhattan borough of New York February 2, 2015. REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY ENVIRONMENT)

Workers shovel away a large puddle of slush in Times Square during a winter storm in the early morning hours in the Manhattan borough of New York February 2, 2015. REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY ENVIRONMENT)

People make their way around a large puddle of slush in Times Square during a winter storm in the early morning hours in the Manhattan borough of New York February 2, 2015. REUTERS/Carlo Allegri (UNITED STATES - Tags: ENVIRONMENT SOCIETY)

Former Croatian Prime Minister Ivo Sanader (2nd R) stands during his trial at a county court in Zagreb March 11, 2014. According to local media, Sanader was sentenced to nine years in prison for creating slush funds for his former conservative HDZ party by siphoning money from public companies during his time in power. REUTERS/Antonio Bronic (CROATIA - Tags: BUSINESS CRIME LAW POLITICS)

Former Croatian Prime Minister Ivo Sanader stands during his trial at a county court in Zagreb March 11, 2014. According to local media, Sanader was sentenced to nine years in prison for creating slush funds for his former conservative HDZ party by siphoning money from public companies during his time in power. REUTERS/Antonio Bronic (CROATIA - Tags: BUSINESS CRIME LAW POLITICS)

A man walks his dog across a slush and snow covered street in the Park Slope section of Brooklyn, New York February 14, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT)

Morning commuters cross a slush and snow covered street in the Park Slope section of Brooklyn, New York February 14, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT)

A woman crosses the street with children through slush and snow in the Park Slope section of Brooklyn, New York February 14, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT)

A woman crosses a slush and snow covered street in the Park Slope section of Brooklyn, New York during the morning commute February 14, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT)

Morning commuters cross a slush and snow covered street in the Park Slope section of Brooklyn, New York February 14, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT)

A fashionista walks though the slush to leave Lincoln Center, the site of New York Fashion Week, in the Manhattan borough of New York February 13, 2014. REUTERS/Carlo Allegri (UNITED STATES - Tags: FASHION ENVIRONMENT)

A fashionista walks thought the slush to leave Lincoln Center, the site of New York Fashion Week, in the Manhattan borough of New York February 13, 2014. REUTERS/Carlo Allegri (UNITED STATES - Tags: FASHION ENVIRONMENT)

Attendees walk though the slush as they arrive at Lincoln Center the site of New York Fashion Week in the Manhattan borough of New York February 13, 2014. REUTERS/Carlo Allegri (UNITED STATES - Tags: FASHION ENVIRONMENT SOCIETY)

Attendees walk though the slush as they arrive at Lincoln Center the site of New York Fashion Week in the Manhattan borough of New York February 13, 2014. REUTERS/Carlo Allegri (UNITED STATES - Tags: FASHION ENVIRONMENT SOCIETY)

A pedestrian makes his way through the slush along Pennsylvania Avenue in Washington, February 13, 2014. A deadly winter storm moved north along the East Coast of the United States on Thursday, bringing heavy snow, sleet and rain across the Washington, D.C., and New York areas, grounding flights and shutting government offices. REUTERS/Jonathan Ernst (UNITED STATES - Tags: POLITICS ENVIRONMENT)

Commuters make their way through the snow and slush during the morning rush in the Park Slope section of Brooklyn, New York February 5, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT SOCIETY)

Commuters make their way through the snow and slush during the morning rush in the Park Slope section of Brooklyn, New York February 5, 2014. REUTERS/Brendan McDermid (UNITED STATES - Tags: ENVIRONMENT SOCIETY)