Learn Spanish (Latin America): Hacía mucho viento; ¡por poco y me estrello contra el rascacielos! - It was very windy; I almost crashed against the skyscraper!

This is the core of the por poco (y) structure. Even though the event (almost crashing) happened in the past, native speakers use the present indicative to make the "near miss" feel more vivid and immediate. You could use the past tense (por poco y me estrellé), but the present tense is very common and natural in spoken Spanish.

What does the y do in por poco y me estrello? Can I leave it out?

The y is an optional colloquial filler used for emphasis, especially in Latin America. You can absolutely say por poco me estrello without changing the meaning. Adding the y just makes the near miss feel a bit more dramatic in storytelling.

Why use Hacía mucho viento instead of something with estaba?

In Spanish, weather conditions like wind, sun, and cold are traditionally expressed with the verb hacer (to make or do). We use the imperfect tense (hacía) here because it is setting the background scene of the story. You might also hear había mucho viento, which is also correct, but you cannot use estaba with a noun like viento.

Why is it me estrello instead of just estrello?