Thank you very much for your corrections!

Can you help me checking these other two paragraphs?
1) Last summer at my friend’s house, before a party, his dog was closed in a room where there was a lot of food for the dinner.(Better: the accident occured at a friend's house before a party) The dog jumped onto the table and ate some of it, then, while he was eating my friend’s dinner, he knocked a box of eggs, that fell off the table and smashed on the floor. Eventually, my friend found out the disaster and he had to call off the party.
2) Last week I went to a mountain resort and I saw a man who tried to jump onto the rail with the snowboard but he fell off and slid down. Afterwards the mountain rescue came over to help him. While they were coming, an avalanche came down the mountain and all the people were buried under the snow.

Thank you

1. Last summer, before a party at my friend's house, his dog was closed in a room where there was a lot of food. The dog jumped... [Order of prepositional phrases is better when they DON'T come between the subject and verb.]

There's a run-on before "then" -- how will you fix it?

...my friend discovered the disaster...

2. Delete the second "I" and put a comma after "snowboard."

comma after the second "mountain"

Have you ever read the link I've posted several times about the use of commas? You are still leaving out commas needed after introductory phrases/clauses and in compound sentences. Why does this continue?
http://grammar.ccc.commnet.edu/grammar/commas.htm
See #s 2 and 3.

Also the information I've posted before about run-ons and how to fix them:
http://grammar.ccc.commnet.edu/grammar/runons.htm
There are 4 quizzes at the bottom of this webpage. You should working on getting them 100% correct so you don't keep making this particular error.

1) Last summer, an unfortunate incident occurred at a friend's house before a party. It involved his dog being left alone in a room filled with food for the dinner. The dog couldn't resist the temptation and jumped onto the table, devouring some of the food. In the process, it accidentally knocked a box of eggs off the table, causing them to smash on the floor. Unfortunately, my friend discovered this disaster and had no choice but to call off the party.

To improve this paragraph further, you may consider rephrasing it as follows:

"One summer, while preparing for a party at a friend's house, a hilarious mishap took place. The friend's dog, left unattended in a room filled with delectable food for the dinner, couldn't resist its cravings. It playfully hopped onto the table, greedily munching on some of the dishes. In doing so, it inadvertently toppled a box of eggs, resulting in a messy spectacle as they splattered onto the floor. The unfortunate turn of events led my friend to reluctantly cancel the planned festivities."

2) Last week, during my visit to a mountain resort, I witnessed a thrilling incident. As I observed, a man attempted to jump onto the rail with his snowboard, seeking an adrenaline rush. Regrettably, his attempt failed, and he ended up falling off the rail, sliding down the mountainside. The situation quickly attracted the attention of the mountain rescue team, who promptly arrived to lend a helping hand. However, as they were en route, a sudden avalanche cascaded down the mountain, burying all the people in its path under a heavy blanket of snow.

To enhance this paragraph, you may consider making the following revision:

"During my recent trip to a mesmerizing mountain resort, an exhilarating spectacle unfolded before my eyes. I caught sight of a daring individual determined to perform a daring snowboarding stunt by leaping onto the rail. However, fortune did not favor him that day, and he lost his balance before plummeting off the rail, uncontrollably descending the mountainside. The heart-stopping escapade immediately summoned the expertise of the mountain rescue team, who swiftly sprung into action, racing to aid the fallen adventurer. Tragically, just as they advanced towards the scene, an unexpected avalanche thundered down the mountain, mercilessly enveloping everyone in the vicinity beneath a formidable cascade of snow."