Snow can trap  exhaust  gases  under your vehicle. 
This  can cause  deadly  CO (carbon  monoxide) 
gas 
to get  inside.  CO could  overcome  you  and kill 
you.  You  can’t  see it  or smell  it, 
so you  might  not 
know  it is  in  your  vehicle.  Clear away  snow  from 
around  the base  of your  vehicle,  especially  any 
that 
is blocking  your exhaust  pipe.  And  check 
around  again  from  time 
to time to be  sure  snow 
doesn’t  collect  there. 
Open  a  window  just 
a little on the  side of the 
vehicle  that’s  away 
from the  wind.  This  will  help 
keep  CO out. 
Run  your  engine  only  as long  as you must.  This  saves 
fuel.  When  you  run  the  engine,  make  it go a little  faster 
than  just idle.  That  is,  push  the  accelerator  slightly.  This 
uses  less fuel for  the  heat  that  you  get  and  it keeps  the 
battery  charged.  You will  need  a  well-charged  battery  to 
restart  the  vehicle,  and  possibly  for signaling  later on 
with  your  headlamps.  Let  the  heater  run  for awhile. 
Then,  shut  the  engine 
off and  close  the  window  almost 
all  the  way  to  preserve  the  heat.  Start the  engine  again 
and  repeat  this only  when  you  feel really  uncomfortable 
from  the  cold. But do it  as  little  as possible.  Preserve  the 
fuel 
as long  as  you  can. To help  keep  warm,  you  can  get 
out  of  the  vehicle  and  do some  fairly  vigorous  exercises 
every  half  hour  or 
s_o until  help  comes. 
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