![2017 U.S. tornado season off to a whirlwind start](/sites/default/files/tornados_2017todate_480.jpg)
The 2017 tornado season across the United States has gotten off to an active start. As of April 22, 570 tornadoes have been reported, which is almost a hundred more than average.
![Wiggle room: why the line tracking sea ice extent is so wavy near the annual winter maximum](/sites/default/files/2-up-480.png)
Compared to their smooth appearance at other times of year, the lines tracking Arctic and Antarctic sea ice extent become wiggly. Why is that?
![2017 Arctic winter maximum and Antarctic summer minimum both set new record lows](/sites/default/files/animation-rotator-480.png)
Despite being at opposite points of the annual cycle, the Arctic and Antarctic had something in common in March 2017: record-low sea ice extents.
![U.S. spring extremes: coldest and warmest first day of spring](/sites/default/files/FirstDayofSpring_highlow_temps_480x320.png)
Based on historical climate data from thousands of stations across the United States, these maps show the warmest and coldest daytime high temperatures ever recorded at a given location on March 19—the astronomical first day of spring.
![2017 U.S. spring climate and flood outlook](/sites/default/files/styles/card_thumb/public/2023-07/2017_springoutlook_480.jpg?itok=SyWWKD4B)
2017 U.S. spring climate and flood outlook
March 16, 2017
![Sea Ice map](/sites/default/files/styles/card_thumb/public/2023-07/seaice_feb12_2017_480.jpg?itok=tp-EMu1L)
Arctic sea ice on track to be among smallest winter maximums on record
February 17, 2017
![Ocean plant growth blooms in springtime as Arctic sea ice thins](/sites/default/files/ArcticPlantGrowth_480.png)
Springtime melting and retreating sea ice allowed more sunlight to reach the upper layers of the ocean, stimulating widespread blooms of algae and other tiny marine plants which form the base of the marine food chain: a sign of the rapid changes occurring in a warming Arctic.