Usually are yellow and diamond-shaped, with black lettering or symbols.
It looks like this "&".
fumes
an abandoned vehicle left in peculiar location
If the meaning is "prior warning" (ie: "warning in advance") then "advance warning" is correct. If the meaning is "further warning" (more urgent than when previously given) then "advanced warning" is correct.
It has a white background and a red (plus sign) cross on it.
A warning sign
The Svalbard polar bear warning sign looks like a signpost, but with a polar bear on it. Some signs show how the polar bear is on a black background of a triangular signpost with reddish edges. On the warning signpost, you may also read signs like 'Stop' or 'Danger, do not walk beyond this sign. Svalbard is in Arctic Ocean, somewhere between North Pole and Norway.
Children Crossing/ a school warning sign
warning
That warning sign said: WARNING! Self destruct on it.
the at sign looks like this: @
Traffic sign Road sign Warning sign Information Visual symbol
Warning Sign - song - was created in 1985.
A warning SIGN - is a sign telling of dangerous conditions ahead
no
shaped like an engine
what does a no power boat ahead sign look like