Breakdown of El tráfico es lentísimo por la tormenta.
ser
to be
el tráfico
traffic
por
for / by / through / in/during (part of the day)
lento
slow
Questions & Answers about El tráfico es lentísimo por la tormenta.
Why do we use por here to mean "because of"? Could I use porque?
In Spanish, por is used to show the cause or reason for something. Here, the storm is the direct cause of the slow traffic. You cannot use porque (because) here, as porque needs to be followed by a full phrase with a verb, like porque hay una tormenta (because there is a storm). When placing the equivalent of "because of" before just a noun like la tormenta, always use por.
The traffic is only slow temporarily because of the storm. Why use es instead of está?
This is a great question that often trips up learners! While estar is often used for temporary states, Spanish speakers frequently use ser to describe the overall nature of an event or a situation happening around them. That said, using está (El tráfico está lentísimo) is also perfectly natural here and emphasizes that it is a temporary condition. Both are common and correct!
What does the -ísimo ending on lentísimo do?