Historical clue formulations

• Time when glaciers form — 2024-07-31
• What was cool for a long time? — 2021-05-13
• Cold that just won't go away? — 2021-04-25
• Cooling-off period? — 2020-12-17
• Glaciologist's concern — 2019-03-03
• 2002 animated film with a woolly mammoth — 2018-12-19
• Mammoth time period — 2018-02-20
• Frigid time, climatically speaking — 2016-02-29
• When mastodons roamed — 2015-11-04
• Big chill? — 2015-03-28
• Hit 2002 film with talking sloths — 2014-09-29
• When mammoths roamed — 2012-10-10
• Big freeze — 2012-07-30
• When mastodons became extinct — 2012-03-28
• Period when Long Island was formed — 2012-03-15
• Period of advancing glaciers — 2010-03-22
• Freezing period — 2009-06-29
• When the Great Lakes were formed — 2009-06-14
• Wintry stretch — 2009-04-03
• When mastodons disappeared — 2008-11-12
• Period ending about 9000 B.C. — 2008-07-14
• Time of advancing glaciers — 2008-04-28
• Cold spell — 2006-12-30
• Glacial period — 2006-07-04
• The Pleistocene Epoch, familiarly — 2006-04-02
• Cooling-off period — 2005-09-24
• The big chill — 2004-04-08
• Frigid time — 2003-12-02
• When mastodons disappeared — 2003-08-26
• Part of the Quaternary Period — 2003-07-18
• When the Great Lakes were formed — 2002-01-06
• Paleontological topic — 2001-08-11
• When glaciers advanced — 2000-10-16
• Pleistocene Epoch, familiarly — 2000-06-14
• Hardly a cold snap — 2000-04-09
• When modern elephants first appeared — 2000-03-17
• Cooling-off period — 2000-03-03
• Quaternary period event — 1999-10-16
• Quaternary division — 1999-07-30
• When mammoths lived — 1999-07-14
• It ended about 10,000 years ago — 1999-05-06
• Pleistocene epoch — 1996-04-20
• Reign of glaciers — 1994-11-02